- •We examined ICD-10-CM SDOH-related Z codes (Z55–Z65) among adults with hypertension.
- •Documentation of SDOH-related Z codes was less than 4% for all 3 insurance groups.
- •Documentation was higher among inpatient claims for all 3 insurance groups.
- •Those with SDOH-related Z codes had more chronic conditions.
- •Medical expenditures were more than 1.5 times higher for those with SDOH-related Z codes.
Tracking social needs can provide information on barriers to controlling hypertension and the need for wraparound services. No recent studies have examined ICD-10-CM SDOH-related Z codes (Z55–Z65) to indicate social needs with a focus on patients with hypertension.
Three cohorts were identified with a diagnosis of hypertension during 2016–2017 and continuously enrolled in fee-for-service (FFS) insurance through June 2021: (1) commercial, age 18–64 (n=1,024,012); (2) private insurance to supplement Medicare (Medicare Supplement), age 65+ (n= 296,340); and (3) Medicaid, age 18+ (n=146,484). Both the proportion of patients and health care encounters or visits with a SDOH-related Z code were summarized annually. Patient and visit characteristics were summarized for 2019.
In 2020, the highest annual documentation of SDOH-related Z codes was among Medicaid beneficiaries (3.02%, 0.46% commercial, 0.42% Medicare supplement); documentation was higher among inpatient than outpatient visits for all insurance types. Z63 (related to primary support group) was more common among commercial and Medicare Supplement beneficiaries, and Z59 (housing and economic circumstances) was more common among Medicaid beneficiaries. The 2019 total unadjusted medical expenditures were 1.85, 1.78, and 1.61 times higher for those with a SDOH-related Z code than those without for commercial, Medicare Supplement, and Medicaid, respectively. Patients with a SDOH-related Z code also had higher proportions of diagnosed chronic conditions. Among Medicaid beneficiaries, differences in the presence of a SDOH-related Z code by race or ethnicity were observed.
Although currently underreported, SDOH-related Z codes provide an opportunity to integrate social and medical data and may help decision makers understand needs for additional services among individuals with hypertension.
Social determinants of health (SDOH) refer to the social and economic conditions of daily life that can result in more social needs and, therefore, affect a range of health and life outcomes. Many health systems are screening and addressing patients’ social needs as part of broader strategies to improve health.1–6 The lack of standardized, national data on social needs linked to health care encounters is a barrier to understanding the patterns and impacts of health system efforts.7 In late 2015, SDOH-related V codes in the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) system were converted to SDOH-related Z codes in the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) code system to indicate social and economic circumstances that are tied to social needs. Z55 (problems related to education and literacy) through Z65 (problems related to other psychosocial circumstances) are standardized for documenting considerations related to SDOH. 8-11
In 2019, the American Hospital Association (AHA) Coding Clinic recommended also using notes from nonphysician providers (e.g., community health workers) for documenting SDOH-related Z codes at hospitals and health systems.12 Nonphysician providers can document using SDOH-related Z codes during any type of encounter.9 SDOH-related Z codes can be an efficient and lower-cost way to share information through medical records and insurance claims among clinicians, hospitals, and health plans. The AHA and multiple professional healthcare organizations promote screening and documenting using SDOH-related Z codes in medical records.13
There are few studies examining patterns of SDOH-related Z codes or the associations of SDOH-related Z codes with outcomes using large hospital discharge, Medicaid, or Medicare fee-for-service (FFS) data.5, 7, 14-17 Several studies including 2 or more years of data reported increasing trends of SDOH-related Z codes over time. Nevertheless, the presence of SDOH-related Z codes (∼2% or lower) was limited in all of these studies. 7,17 In addition, few studies have focused on specific electronic health record systems.18-20
Hypertension is a significant public health problem; approximately 50% of adults in the United States have hypertension.21 Attributable to high blood pressure, the death rate increased by 34.2% and the number of deaths increased by 65.3% from 2009 to 2019.22 Timely diagnosis and adequate blood pressure treatment are essential for preventing adverse outcomes of hypertension, including stroke and associated disability and death.22, 23
In a Centers for Medicare & Medicaid Services (CMS) study of Medicare FFS beneficiaries in 2017, hypertension was the most common condition (72%) reported among 467,136 beneficiaries with a SDOH-related Z code.16 The results of the CMS study indicate a need to consider social needs and health and that hypertension may be a particularly relevant chronic condition. No recent SDOH-related Z code studies have focused solely on patients with hypertension to better understand patterns. The present study updates the literature by year and beneficiary type and by focusing on a specific chronic condition. We examined the presence of SDOH-related Z codes among patients with hypertension enrolled in commercial, Medicare Supplement, or Medicaid insurance plans and their health care encounters from January 1, 2018, to June 30, 2021. This research may inform larger efforts to track social need barriers to hypertension control and for providing wraparound services to improve patient care and well-being.24,25 To expand the literature on this topic we:
- •explored whether documentation of SDOH-related Z codes increased over time by encounter setting;7,17
- •described what SDOH-related Z codes were documented; and
- •described patterns of health care use and patient characteristics associated with the presence of an SDOH-related Z code.5, 14, 15 To avoid associations with the COVID-19, this analysis was conducted for 2019 as it was the most recent year prior to the pandemic.
We used the MarketScan® Research Databases: Commercial Claims and Encounters (CCAE), Medicare Supplement, and Medicaid from January 1, 2016, to June 30, 2021. The CCAE contains inpatient, emergency department (ED), and outpatient claims among enrollees and their dependents from employer-sponsored commercial health insurance plans. The CCAE is collected from more than 300 employers, more than 30 health plans, and over 500 hospitals in the United States. The Medicare Claims Database contains claims information for retirees with employer-sponsored supplemental health plans. The Medicaid data represents beneficiaries from 5–8 de-identified states (states varies by year). We accessed all data through Treatment Pathways (TxP), a tool to extract data through a cloud-based online query.26 All data were de-identified, and this study was exempt from review by the Institutional Review Board of the Centers for Diseases Control and Prevention.
We derived 3 study cohorts that were based on beneficiaries in different insurance plans: commercial insurance, Medicare Supplemental, and Medicaid. As shown in Figures 1A and 1B, we used data from January 1, 2016, through December 31, 2017, to identify our study cohorts using age and hypertension diagnoses. We used data from January 1, 2018, through June 30, 2021 for additional inclusion and exclusion criteria and for our analyses. We restricted the patients to ages 18–64 years for the commercial cohort, age 65 years or older for the Medicare cohort, and age 18 years or older for the Medicaid cohort. In addition, we included patients with at least one diagnosis of hypertension (International Classification of Diseases, Tenth Revision, Clinical Modification [ICD-10-CM] diagnosis code of I10-I15,27 (Appendix Table 1) in inpatient, ED, or outpatient claims from January 1, 2016, through December 31, 2017, and continuously enrolled from January 1, 2018, through June 30, 2021, in noncapitated or fee-for-service health insurance. The requirement for continuous enrollment in fee-for-service health insurance was implemented for comparable health care use and cost patterns. Finally, to exclude patients with gestational hypertension and pregnancy-related healthcare, we excluded patients with a pregnancy diagnosis at any point from January 2016 through June 2021 (Appendix Table 2). Our final study cohorts were: commercial (n=1,024,012); Medicare Supplement (n=296,340); and Medicaid (n=146,484) (Figures 1A and 1B).
Table 1Patient Characteristics at First Diagnosis, Patients with Established Hypertension 2016-2017 in MarketScan® Commercial Claims and Encounters, Medicare Supplement, and Medicaid Database
|Age at first dx, Mean (SD)||50.1 (8.0)||72.5 (7.2)||47.8 (11.3)|
|Female, N (%)||474,496 (46.34%)||162,803 (54.94%)||87,467 (59.71%)|
|Urban, N (%)||860,007 (83.98%)||254,216 (85.79%)||-|
|Northeast, N (%)||228,821 (22.35%)||141,960 (47.90%)||-|
|South, N (%)||519,330 (50.72%)||61,863 (20.88%)||-|
|Midwest, N (%)||185,264 (18.09%)||84,324 (28.46%)||-|
|West, N (%)||88,576 (8.65%)||8,046 (2.72%)||-|
|Non-Hispanic White, N (%)||-||-||62,573 (42.72%)|
|Non-Hispanic Black, N (%)||-||-||62,164 (42.44%)|
|Hispanic, N (%)||-||-||2,661 (1.82%)|
|Other race, N (%)||-||-||4,055 (2.77%)|
Table 2Proportion of Patients with a SDOH-related Z code, and Proportion by SDOH Domain among Patients with Established Hypertension, and by Insurance Type and Year Documented
for select states
|% of patients with 1+ SDOH-related Z code||0.389||0.438||0.461||0.306||0.382||0.417||3.132||3.117||3.019|
|Number of unique patients who had 1± SDOH-related Z code||14,680||16,230||19,514||2,498||3,409||3,616||34,764||40,565||32,627|
|Z codes by SDOH domain||%||%||%||%||%||%||%||%||%|
|Z55: problems related to education and literacy||0.28||0.51||0.67||0.28||0.09||0.47||0.45||0.96||1.60|
|Z56: problems related to employment and unemployment||9.46||8.88||8.29||0.60||0.65||1.11||1.46||1.92||3.17|
|Z57: occupational exposure to risk factors||1.22||1.19||1.04||1.64||1.41||1.24||0.23||0.08||0.06|
|Z58: problems related to physical environment||0.00||0.00||0.00||0.00||0.00||0.00||0.00||0.00||0.00|
|Z59: problems related to housing and economic circumstances||2.33||2.11||2.31||2.56||4.08||4.48||80.83||81.12||71.46|
|Z60: problems related to social environment||5.39||4.49||4.63||27.06||29.10||24.23||4.19||4.85||8.87|
|Z62: problems related to upbringing||12.87||13.71||12.47||6.16||5.72||5.17||2.39||2.48||4.61|
|Z63: other problems related to primary support group||62.75||63.91||64.96||53.28||50.78||55.09||6.90||5.80||8.05|
|Z64: problems related to certain psychosocial circumstances||0.19||0.35||0.13||0.04||0.06||0.00||0.03||0.05||0.03|
|Z65: problems related to other psychosocial circumstances||5.52||4.87||5.51||8.37||8.13||8.21||3.52||2.75||2.15|
Note: The proportion of SDOH-related Z codes is calculated by dividing the total number of encounters observed with each SDOH-related Z code by the total number of SDOH-related Z codes in all encounters (identified with ICD-10-CM of Z55-Z65). The proportions were calculated by SDOH-related Z code domain, year documented, and insurance. Proportions sum to 100%. Patients with established hypertension were defined if at least one inpatient, emergency department, or outpatient hypertension diagnosis (ICD-10-CM=I10-I15) from January 1, 2016, to December 31, 2017.
Essentially, the analysis populations were identified with hypertension January 1, 2016, through December 31, 2017 and their subsequent health care encounters were examined for analysis. Thus, we required continuous enrollment for the entire time period to examine the trends in SDOH-related Z codes. We explored whether documentation increased over time for more recent years.7,17 To avoid associations with the COVID-19 pandemic or COVID-19 related disruptions, some results are presented for 2019, the most recent year prior to the COVID-19 pandemic.
Timepoints for inclusion of patients and analysis:
|January 1, 2016-December 31, 2017||January 1, 2018-June 30, 2021|
|Inclusion criteria:||Hypertension identified and enrolled||Continued to be enrolled.|
The following SDOH-related Z codes were included: Z55 (problems related to education and literacy), Z56 (problems related to employment and unemployment), Z57 (occupational exposure to risk factors), Z58 (problems related to physical environment), Z59 (problems related to housing and economic circumstances), Z60 (problems related to social environment), Z62 (problems related to upbringing), Z63 (other problems related to primary support group), Z64 (problems related to certain psychosocial circumstances), and Z65 (problems related to other psychosocial circumstances) (Appendix Table 1).9
First, to explore whether documentation of SDOH-related Z codes increased over time by encounter setting, 7,17 we summarized data over time per patient and per encounter and calculated changes: the proportion of unique patients with any claim with an SDOH-related Z code by insurance type was summarized by quarter from January 2018 to June 2021 (Figure 2); and 2) the proportion of encounters with SDOH-related Z codes by insurance type was stratified by settings and summarized by quarter from January 2018 to June 2021 (Figure 3). Overall differences between groups within insurance type and between insurance type were evaluated using a two-proportion Z-test. To quantify the change over time, the percentage change was calculated for each group and presented with the trends:
[(proportion SDOH-related Z code present in second quarter of 2021 – proportion SDOH-related Z code present first quarter of 2018) /
(SDOH-related Z code present in first quarter of 2018)] x 100.
Where a higher percent indicates there was a larger increase over time in the proportion of health care encounters where SDOH-related Z codes were documented. Second, to describe what SDOH-related Z codes were documented, the proportion of SDOH-related Z codes by SDOH domain and insurance type was summarized by year from 2018 to 2020 (Table 2).
Finally, to describe the patterns of health care use and patient characteristics associated with the presence of an SDOH-related Z code,5, 14, 15 we summarized patient and encounter characteristics, stratified by patients with an SDOH-related Z code versus those without an SDOH-related Z code, in 2019, the most recent year prior to the COVID-19 pandemic (Table 3). These included: total annual medical net payments made by health plan by encounter type; the number of annual medical services by encounter type, and patient characteristics (age, sex, and clinical diagnoses for all patients; and race/ethnicity, Census region, and urbanicity of residence, if available). Health was characterized by using the Quan modification of the Charlson Comorbidity Index (CCI) for ICD-10-CM codes (Appendix Table 3),28 including both continuous and categorized (0, 1, 2, 3+) measures for 2019. To assess differences between patients with and without an SDOH-related Z code, the Wilcoxon rank-sum test, for nonparametric data, was used for continuous variables, and the Pearson's Chi-square test was used for categorical variables.
Table 3Health Care Use and Patient Characteristics Among Patients with Established Hypertension in MarketScan® Commercial Claims and Encounters, Medicare Supplement, and Medicaid Database, 2019
|SDOH-related Z code in 2019 = No||SDOH-related Z code in 2019 = Yes||SDOH-related Z code in 2019 = No||SDOH-related Z code in 2019 = Yes||SDOH-related Z code in 2019 = No||SDOH-related Z code in 2019 = Yes|
|Medical costs and utilization of services, Mean (SD)|
|Total Medical Net Payments||$11,240.9 (34260.7)||$20,834.0⁎⁎⁎ (50122.1)||$6,126.0 (18679.0)||$10,883.5⁎⁎⁎ (23473.2)||$22,993.0 (36416.0)||$37,014.7⁎⁎⁎ (40038.9)|
|Total Inpatient Net Payments||$2,373.6 (19425.3)||$6,012.6⁎⁎⁎ (31223.9)||$1,259.6 (9826.2)||$3,015.1⁎⁎⁎ (13181.7)||$,3118.1 (13453.0)||$10,265.0⁎⁎⁎ (22963.2)|
|Total ED Net Payments||$511.3 (2531.5)||$1,267.4⁎⁎⁎ (3964.5)||$163.8 (795.1)||$497.8⁎⁎⁎ (1894.3)||$977.9 (2474.6)||$3,586.1⁎⁎⁎ (7900.1)|
|Total Outpatient Net Payments||$4,783.6 (18699.6)||$8,834.6⁎⁎⁎ (26422.2)||$2,788.9 (9465.3)||$4,834.8⁎⁎⁎ (9567.6)||$11,260.7 (23907.0)||$13,734.8⁎⁎⁎ (21657.0)|
|Total Pharmacy Net Payments||$3,284.1 (13211.3)||$4,155.4⁎⁎⁎ (12467.3)||$1,799.4 (8793.5)||$2,377.6* (9823.0)||$7,028.6 (17914.8)||$8,434.3⁎⁎⁎ (15193.5)|
|Number of Inpatient Encounters||0.1 (0.4)||0.3⁎⁎⁎ (0.8)||0.2 (0.5)||0.3⁎⁎⁎ (0.7)||0.3 (1.0)||1.4⁎⁎⁎ (2.7)|
|Number of ED Encounters||0.3 (0.9)||0.8⁎⁎⁎ (2.1)||0.4 (1.1)||1.1⁎⁎⁎ (2.3)||1.5 (3.4)||5.7⁎⁎⁎ (12.4)|
|Number of Outpatient Encounters||13.2 (15.7)||24.5⁎⁎⁎ (21.6)||23.3 (21.4)||34.8⁎⁎⁎ (26.7)||58.8 (99.6)||83.2⁎⁎⁎ (103.9)|
|Number of Pharmacy Encounters||25.3 (23.2)||33.8⁎⁎⁎ (28.1)||32.5 (24.4)||38.5⁎⁎⁎ (28.4)||67.6 (71.3)||74.1⁎⁎⁎ (66.7)|
|Dummy indicators of having any of the ICD-10-CM diagnosis of 17 conditions from the Charlson Comorbidity Index in any setting, N (%)|
|Myocardial infarction||15,841 (1.55%)||110⁎⁎⁎ (2.45%)||12,009 (4.07%)||65⁎⁎ (5.74%)||7,387 (5.21%)||406⁎⁎⁎ (8.89%)|
|Congestive heart failure||29,771 (2.92%)||165⁎⁎ (3.68%)||34,558 (11.71%)||165⁎⁎ (14.56%)||17,124 (12.07%)||728⁎⁎⁎ (15.94%)|
|Peripheral vascular disease||38,320 (3.76%)||201* (4.49%)||58,813 (19.92%)||242 (21.36%)||14,800 (10.43%)||558⁎⁎⁎ (12.22%)|
|Cerebrovascular disease||10,734 (1.05%)||80⁎⁎⁎ (1.79%)||13,352 (4.52%)||87⁎⁎⁎ (7.68%)||7,134 (5.03%)||327⁎⁎⁎ (7.16%)|
|Dementia||856 (0.08%)||16⁎⁎⁎ (0.36%)||11,504 (3.90%)||121⁎⁎⁎ (10.68%)||3,275 (2.31%)||116 (2.54%)|
|Chronic pulmonary disease||113,871 (11.17%)||752⁎⁎⁎ (16.78%)||57,375 (19.44%)||279⁎⁎⁎ (24.62%)||44,971 (31.69%)||2,055⁎⁎⁎ (45.01%)|
|Rheumatic disease||22,967 (2.25%)||125* (2.79%)||12,057 (4.08%)||48 (4.24%)||4,935 (3.48%)||186* (4.07%)|
|Peptic ulcer disease||6,376 (0.63%)||48⁎⁎⁎ (1.07%)||3,331 (1.13%)||17 (1.50%)||2,103 (1.48%)||99⁎⁎⁎ (2.17%)|
|Mild liver disease||51,892 (5.09%)||341⁎⁎⁎ (7.61%)||14,247 (4.83%)||74⁎⁎ (6.53%)||12,226 (8.61%)||704⁎⁎⁎ (15.42%)|
|Diabetes without chronic complication||249,189 (24.44%)||1,138 (25.40%)||88,833 (30.09%)||332 (29.30%)||48,686 (34.31%)||1,869⁎⁎⁎ (40.93%)|
|Diabetes with chronic complication||68,861 (6.75%)||363⁎⁎⁎ (8.10%)||44,336 (15.02%)||185 (16.33%)||23,622 (16.64%)||971⁎⁎⁎ (21.27%)|
|Hemiplegia or paraplegia||3,187 (0.31%)||34⁎⁎⁎ (0.76%)||2,621 (0.89%)||17* (1.50%)||4,746 (3.34%)||198⁎⁎⁎ (4.34%)|
|Renal disease||42,342 (4.15%)||186 (4.15%)||43,749 (14.82%)||182 (16.06%)||13,928 (9.81%)||538⁎⁎⁎ (11.78%)|
|Any malignancy, including lymphoma and leukemia, except malignant neoplasm of skin||49,323 (4.84%)||247* (5.51%)||46,310 (15.69%)||183 (16.15%)||6,637 (4.68%)||257⁎⁎ (5.63%)|
|Moderate or severe liver disease||2,084 (0.20%)||22⁎⁎⁎ (0.49%)||786 (0.27%)||3 (0.26%)||1,200 (0.85%)||78⁎⁎⁎ (1.71%)|
|Metastatic solid tumor||5,539 (0.54%)||47⁎⁎⁎ (1.05%)||4,428 (1.50%)||31⁎⁎⁎ (2.74%)||1,075 (0.76%)||47* (1.03%)|
|AIDS/HIV||3,739 (0.37%)||25* (0.56%)||280 (0.09%)||1 (0.09%)||2,790 (1.97%)||184⁎⁎⁎ (4.03%)|
|Charlson Comorbidity Index Score=0, N (%)||566,646 (55.58%)||2,218⁎⁎⁎ (49.50%)||88,841 (30.09%)||291⁎⁎ (25.68%)||48,914 (34.47%)||914⁎⁎⁎ (20.02%)|
|Charlson Comorbidity Index Score=1, N (%)||243,129 (23.85%)||1,127* (25.15%)||62,321 (21.11%)||233 (20.56%)||30,136 (21.23%)||1,024 (22.43%)|
|Charlson Comorbidity Index Score=2, N (%)||89,916 (8.82%)||458⁎⁎⁎ (10.22%)||46,571 (15.78%)||182 (16.06%)||18,356 (12.93%)||710⁎⁎⁎ (15.55%)|
|Charlson Comorbidity Index Score>=3, N (%)||119,840 (11.75%)||678⁎⁎⁎ (15.13%)||97,474 (33.02%)||427⁎⁎⁎ (37.69%)||44,512 (31.36%)||1,918⁎⁎⁎ (42.01%)|
|Charlson Comorbidity Index Score, Mean (SD)||0.9 (1.5)||1.1⁎⁎⁎ (1.8)||2.1 (2.3)||2.4⁎⁎⁎ (2.6)||2.0 (2.4)||2.8⁎⁎⁎ (2.8)|
|Age at first dx, Mean (SD)||50.1 (8.0)||48.5⁎⁎⁎ (8.6)||72.5 (7.2)||73.8⁎⁎⁎ (7.8)||47.8 (11.4)||47.4* (10.3)|
|Female, N (%)||471,918 (46.29%)||2,578⁎⁎⁎ (57.53%)||162,073 (54.90%)||730⁎⁎⁎ (64.43%)||84,942 (59.85%)||2,525⁎⁎⁎ (55.30%)|
|Urban, N (%)||856,167 (83.98%)||3,840⁎⁎ (85.70%)||253,257 (85.79%)||959 (84.64%)||-||-|
|Northeast, N (%)||227,865 (22.35%)||956 (21.33%)||141,507 (47.93%)||453⁎⁎⁎ (39.98%)||-||-|
|South, N (%)||517,241 (50.73%)||2,089⁎⁎⁎ (46.62%)||61,663 (20.89%)||200⁎⁎ (17.65%)||-||-|
|Midwest, N (%)||184,356 (18.08%)||908⁎⁎⁎ (20.26%)||83,883 (28.41%)||441⁎⁎⁎ (38.92%)||-||-|
|West, N (%)||88,056 (8.64%)||520⁎⁎⁎ (11.60%)||8,007 (2.71%)||39 (3.44%)||-||-|
|Non-Hispanic White, N (%)||-||-||-||-||60,783 (42.83%)||1,790⁎⁎⁎ (39.20%)|
|Non-Hispanic Black, N (%)||-||-||-||-||59,930 (42.23%)||2,234⁎⁎⁎ (48.93%)|
|Hispanic, N (%)||-||-||-||-||2,603 (1.83%)||58⁎⁎ (1.27%)|
|Other race, N (%)||-||-||-||-||3,972 (2.80%)||83⁎⁎⁎ (1.82%)|
Note: P-values were obtained from the Wilcoxon rank-sum test for continuous variables and Pearson's Chi-squared test for dummy indicators for comparisons between the presence of SDOH-related Z code versus not. Total medical net payments are the average of payments made by insurance plans in 2019. Total inpatient, ED, outpatient, and pharmacy payments are the average of the total inpatient, ED, outpatient, and pharmacy payments made by insurance plans in 2019. The number of inpatients, ED, outpatient, and pharmacy visits are the average numbers of inpatient, ED, outpatient, and pharmacy visits in 2019. The ICD-10-CM codes to identify the Charlson CI dummy variables are in the Appendix Table 3. All the dummy variables for the diseases were identified as equal one if at least one ICD-10-CM code of the respective ICD-10-CM were identified in any settings. Patients with established hypertension were defined if there were at least one inpatient, emergency department, or outpatient hypertension diagnosis (ICD-10-CM=I10-I15) from January 1, 2016, to December 31, 2017. Dash (-) indicates that data are not available in the respective databases. *P-value<0.05 ** P-value<0.01 *** P-value<0.001.
P-values of < 0.05 were used to indicate statistical significance. All analyses were conducted by using Stata MP version 14.2 (StataCorp, College Station, TX) in 2022.
Table 1 shows summaries of the available patient characteristics at first hypertension diagnosis, which, was identified for the analysis cohorts in 2016-2017. Of 1,024,012 (commercial insurance aged 18−64 years), 296,340 (Medicare Supplement aged ≥65 years), and 146,484 (Medicaid aged ≥18 years) patients with established hypertension (Figure 1A, Figure 1B), the average age was 50 for commercial beneficiaries, 73 for Medicare Supplement beneficiaries, and 48 for Medicaid beneficiaries. The proportion of patients who were female ranged from 46% among commercial beneficiaries to nearly 60% among Medicaid.
Exploration of whether documentation of SDOH-related Z codes increased over time by encounter setting
Quarterly proportion of unique patients with any claim with an SDOH-related Z code
All differences over time and between insurance groups were statistically significant (p<0.001). While the absolute increases in the proportion of SDOH-related Z code documented from 2018 to 2021 were small, the relative increases were 46.9% (from 0.11% to 0.16%) among patients with Medicare supplemental insurance, and 13.8% (from 1.31% to 1.49%) among patients with Medicaid, from the first quarter of 2018 through the second quarter of 2021 (Figure 2). In addition, there appeared to be a dip in SDOH-related Z codes among patients with Medicaid during the beginning of the COVID-19 pandemic. The annual proportions of patients with Z codes were 0.39%, 0.44%, and 0.46% in 2018, 2019, and 2020, respectively, for commercial insurance; 0.31%, 0.38%, and 0.42% in 2018, 2019, and 2020, respectively, for Medicare Supplement; and 3.13%, 3.12%, 3.02% in 2018, 2019, and 2020, respectively, for Medicaid insurance (Table 2).
Proportion of claims with an SDOH-related Z code
The proportion of claims with a SDOH-related Z code was higher among inpatient than outpatient or ED settings in all 3 insurance types (Figures 3A-C; p<0.001 for all comparisons). Quarterly, approximately 0.37% (vs 0.12% outpatient or 0.09% ED), 0.12% (0.05% outpatient or 0.05% ED), and 2.09% (0.35% outpatient or 1.38% ED) of inpatient encounters contained SDOH-related Z codes in commercial, Medicare supplement, and Medicaid insurances, respectively. The largest increases over time were observed among ED encounters: 169% for commercial, 73% for Medicare Supplement, and 182% for Medicaid from first quarter to last quarter (2018 to mid-2021; p<0.001 for all comparisons).
Documentation of SDOH-related Z codes - proportion by SDOH domain
Z63 (other problems related to primary support group) was the most documented SDOH-related Z code among patients with commercial insurance (62.75%–64.96% of all SDOH-related Z code encounters 2018–2020) and Medicare Supplement (50.78%–55.09% of all SDOH-related Z code encounters 2018–2020), whereas Z59 (problems related to housing and economic circumstances) was most common among patients with Medicaid insurance (71.46%–81.12% of all SDOH-related Z code encounters 2018–2020) (Table 2).
Patterns of health care use and patient characteristics associated with an SDOH-related Z code
There were 4,481 (0.44%), 1,133 (0.38%), and 4,566 (3.12%) patients who had 1+ SDOH-related Z codes in the 2019 claims database in commercial, Medicare Supplement, and Medicaid insurance, respectively (Table 3). The unadjusted annual total medical, total inpatient, ED, and outpatient net health plan payments were higher among patients with SDOH-related Z codes than those without SDOH-related Z codes across all 3 insurance types (Table 3; all p-values <0.001). On average, the 2019 total expenditures for patients with a SDOH-related Z code were 1.85, 1.78, and 1.61 times higher than patients without a SDOH-related Z code for commercial, Medicare Supplement, and Medicaid insurance, respectively. Patients with 1+ SDOH-related Z codes also tended to have higher number of encounters and proportions of the 17 CCI conditions than those without a SDOH-related Z code. The mean CCI scores were higher among patients with 1+ SDOH-related Z codes than those without a SDOH-related Z code for commercial (1.1 vs 0.9; P<0.001), Medicare Supplement (2.4 vs 2.1; P<0.001), and Medicaid insurance (2.8 vs 2.0; P<0.001). The proportion of females was higher among patients with 1+ SDOH-related Z codes than those without a SDOH-related Z code for commercial (57.5% vs 46.3%; P<0.001) and Medicare Supplement (64.4% vs 54.9%; P<0.001) insurance, but lower for those with Medicaid insurance (55.3% vs 59.9; P<0.001). Additional patient characteristics were available by insurance type. Among Medicaid, the proportion of non-Hispanic Black persons was higher among patients with SDOH-related Z codes than those without SDOH-related Z codes (48.93% vs 42.23%; P<0.001). Similar patterns were observed for 2018 (not shown).
We examined commercial, Medicare Supplement, and Medicaid beneficiaries with hypertension 2016–2017 and continuously enrolled through June 30, 2021. We found the highest documentation of SDOH-related Z codes was among Medicaid beneficiaries (ranged 3.02% to 3.13% annually). The annual proportion of patients with 1+ SDOH-related Z codes ranged from 0.39% to 0.46% for commercial beneficiaries and from 0.31% to 0.42% for Medicare beneficiaries. Patients with a SDOH-related Z code had more comorbidities and higher annual total unadjusted expenditures compared to those without a SDOH-related Z code across all insurance types. Among all SDOH-related Z codes, problems related to primary support group (Z63) were most common among commercial (63%–65%) and Medicare Supplement (51%–55%) beneficiaries, whereas problems related to housing and economic circumstances were the most common among Medicaid beneficiaries (71%–81%).
In our study, SDOH-related Z codes were approximately seven times higher among Medicaid beneficiaries compared to commercial and Medicare beneficiaries. This may reflect screening and documenting practices16, 29 and patient needs. Despite this pattern, the presence of SDOH-related Z codes was low among adult patients with hypertension across all 3 cohorts (≤3%) including Medicaid. This seems to be contrary to national research that suggests more than half (54%) of US adults with low income had unmet social needs.29, 30 Across different periods, analysis populations, and SDOH domains studied, the overall presence of SDOH-related Z codes at the encounter- or claims-level and patient-level has been consistently low (<3%) in other studies.5, 7, 14- 17, 31 Adoption of SDOH-related Z codes has been slow because of a misunderstanding that only physicians can document a patient's social needs, absence of standard operating procedures for documenting and coding, and unfamiliarity with SDOH-related Z codes among healthcare administrators, providers, and coders.13 It has been suggested that SDOH-related Z codes could be used for payment and that reimbursement policies could lead to better documentation using SDOH-related Z codes. 2, 11, 14
Despite the low documentation, associations between the presence of SDOH-related Z codes and more healthcare use and costs were observed in the present study and other studies. 5, 14, 15 For example, a dose-response relationship was found between the number of SDOH domains and hospital readmission (2017 nationwide HCUP); 14 and the presence of SDOH-related Z codes was associated with 4 times the hospitalizations and ED visits and 9.3 times the annual cost per patient (2017 Florida HCUP). 5 In the present study of patients with hypertension, the 2019 total unadjusted expenditures were 1.85, 1.78, and 1.61 times higher for those with a SDOH-related Z code than those without for commercial, Medicare Supplement, and Medicaid, respectively. Moreover, the Medicaid cohort, which had the highest presence of SDOH-related Z codes and the highest rate of housing and economic issues, had the highest mean total net payments, among all types of encounters. In addition, SDOH-related Z codes tended to be more common for inpatient encounters compared to other encounter types. This could represent differences in social needs documentation across settings or that some inpatient primary diagnoses are more obviously related to social and economic circumstances. 5, 16 Across all of these patterns, differences likely reflect a mix of factors and are not attributed to social needs alone. However, identifying social needs among patients with hypertension is an opportunity to prevent adverse outcomes and complications. 24
The Surgeon General's Call to Action acknowledges that improving hypertension control requires addressing SDOH, and screening for social and economic circumstances and social needs among hypertension patients has been recommended.23, 32 SDOH and social needs can be a barrier to healthy living (e.g., unhealthy built environments), accessing, and paying for recommended diagnostics and referrals to recommended care,33 and have been shown to be associated with antihypertensive medication nonadherence at the county-level.34 Even among those taking antihypertensive medications by medication class, differences in the proportion of adults with controlled hypertension have been observed by race/ethnicity and socioeconomic status.35 This suggests some patients with hypertension need additional support for healthcare and lifestyle management, which has implications for cardiovascular disease risk. For example, among a national, population-based sample (age ≥45 years) without coronary heart disease (CHD) at baseline, greater SDOH burdens were associated with fatal incident CHD compared to those without SDOH burdens.25
In the present study we observed larger pharmacy payments and more comorbidity for patients with an SDOH-related Z code compared to those without an SDOH-related Z code across all three cohorts, with a notable difference in diabetes comorbidity among Medicaid patients. Patients with hypertension and social needs may need to navigate systems for resources to pay for medications and additional services to support blood pressure monitoring, medication adherence, and for lifestyle changes. 31, 32 While it is not the purpose of SDOH-related Z codes, monitoring social needs can help clinical and public health decisionmakers understand the population-wide need for such services, potentially by specific chronic conditions.1, 33
Although there are potential benefits to documenting social needs with SDOH-related Z codes, to date, this has not been mandated 2 For example, a small review of records for high-risk patients found that 92% of patients had information that could have been coded but were not documented with SDOH-related Z codes. 36 There are efforts to increase documentation of social needs with SDOH-related Z coding in clinical practice. The AHA recently updated guidance to recommend that administrators raise awareness and educate physicians, other healthcare providers, and medical coders on how to screen, document, and code data on patients' social needs. The AHA guideline suggests that healthcare providers transfer information provided by patients from self-screening tools into the patients' electronic health records. The tools should be available in numerous languages and forms (e.g., with voice instructions) for different levels of literacy. The health care providers could use this information to refer patients to community resources and follow up.13 In the future there may be more coding of social needs and incentive to use SDOH-related Z codes. For example, Accountable Care Organizations (ACO) provide care for the whole person including social needs and CMS is testing different ACO models to advance health equity.37, 38
Although our study expands the existing literature, there are some limitations. First, we cannot generalize our results to other populations, such as those with discontinuous enrollment, those who are uninsured or insured with other types of plans, and the general population. We focus on continuously enrolled beneficiaries who have received health care and had diagnosed hypertension. It is possible that patients with social needs are less likely to have stable access to commercial health insurance because of job insecurity, or that patients may move in and out of Medicaid on the basis of need. It is also possible that patients with social needs have additional barriers to receiving health care and, therefore, have fewer opportunities to diagnose hypertension.39 Second, our data may not be representative of all Medicare or Medicaid populations as we focus on Medicare patients with employer-sponsored supplemental health plans and Medicaid beneficiaries from selected, unidentified states. In addition, there are several reasons why SDOH-related Z codes are underused; thus, screening and documenting for social needs in clinical practice is underreported. Previous studies reported screening for SDOH in a range of 15%–24%.20, 40, 41 Z codes are nonbillable codes, and coders do not have financial incentive to document them. 5 Although SDOH-related Z codes match most domains included in screening tools, not all SDOH screening domains have a corresponding ICD-10-CM Z code2; therefore, the usage patterns in our study may underestimate screening in clinical practice. Third, our data included race or ethnicity information only for Medicaid, and we found a higher proportion of SDOH-related Z codes among non-Hispanic Black beneficiaries. This is consistent with another study using 2019 Medicare fee-for-service data where documentation tended to be higher among Black and American Indian / Native Alaskan benficiaries.17 Future studies are needed to examine if these findings persist among beneficiaries with commercial insurance and to confirm if these results reflect racial or ethnic disparities and not ascertainment bias.
We found the presence of SDOH-related Z codes among individuals with hypertension was low but tended to be associated with poorer health and more with higher expenditures. Documentation of social needs through SDOH-related Z codes provides an actionable opportunity to integrate social and medical data.2 Our study of adults suggests that this may be a missed opportunity to addressing nonclinical needs that affect hypertension and other health outcomes and healthcare costs.
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CRediT authorship contribution statement
Jun Soo Lee: Writing – original draft, Writing – review & editing, Formal analysis, Methodology, Conceptualization. Kara E. MacLeod: Writing – original draft, Writing – review & editing, Formal analysis, Methodology, Conceptualization. Elena V. Kuklina: Writing – review & editing, Conceptualization. Xin Tong: Writing – review & editing, Conceptualization. Sandra L. Jackson: Writing – review & editing, Conceptualization.
Declaration of interests
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper
The authors declare the following financial interests/personal relationships which may be considered as potential competing interests
We would like to acknowledge Feijun Luo, Michael Schooley, Adam Vaughan, and Fátima Coronado, with the Centers for Disease Control and Prevention, for their expertise and manuscript review.
The findings and conclusions in this article are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention. Use of trade names and commercial sources is for identification only and does not imply endorsement by the U.S. Department of Health and Human Services.
Jun Soo Lee and Kara E. MacLeod are joint 1st author with equal contribution.
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
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