Abstract
This cohort analysis evaluates the association of low socioeconomic status with hidradenitis suppurativa among patients in the United States.
Socioeconomic status (SES) is a critical determinant of health outcome; however, no previous studies, to our knowledge, have evaluated SES among patients with hidradenitis suppurativa (HS) in the United States. Therefore we sought to determine whether HS was associated with low SES in a US population-based sample.
Methods
This cross-sectional cohort analysis used multiple health systems data that constitute the data analytics and research platform (Explorys) developed by the IBM Corporation Watson Health team. Clinical information from electronic medical records, laboratories, practice management systems, and claims systems was matched using the single set of Unified Medical Language System ontologies to create longitudinal records for unique patients. The data were standardized and curated according to common controlled vocabularies and classifications systems, including the International Classification of Diseases, SNOMED-CT (Systemized Nomenclature of Medicine–Clinical Terms), LOINC (Logical Observation Identifiers Names and Codes), and RxNorm. We compared the prevalence of low SES among patients with and without HS. The SNOMED-CT term hidradenitis was used to identify patients with HS.1 The primary outcome of interest was Medicaid insurance status, which was used as a proxy for low SES.2 The study population included adults aged 18 to 64 years with an active status in the database within the past 3 years and complete information on age, sex, race/ethnicity, and body mass index. Prevalence was compared using an adjusted odds ratio from a logistic regression model controlling for age, sex, race/ethnicity, obesity, and smoking status. This study was approved by the human subjects committee at the Feinstein Institute for Medical Research at Northwell Health, Manhasset, New York, which waived the need for informed consent for these deidentified data.
Results
We identified 27 615 patients with HS whose characteristics are described in the Table (24.0% men and 76.0% women). Low SES occurred among 6195 patients with HS (22.4%) compared with 898 130 of 6 633 750 patients without HS (13.5%; P < .001). Hidradenitis suppurativa was associated with low SES in the crude analysis (odds ratio, 1.85; 95% CI, 1.80-1.90). In multivariable analysis, the association was significant with only a modest effect size (odds ratio, 1.13; 95% CI, 1.09-1.16).
Table. Characteristics of Patients With and Without HS.
| Characteristic | Study Population, No. (%)a | |
|---|---|---|
| With HS (n = 27 615) | Without HS (n = 6 633 750) | |
| Sex | ||
| Male | 6615 (24.0) | 2 789 940 (42.1) |
| Female | 21 000 (76.0) | 3 843 810 (57.9) |
| Age, y | ||
| 18-29 | 6465 (23.4) | 1 484 140 (22.4) |
| 30-39 | 7145 (25.9) | 1 318 630 (19.9) |
| 40-49 | 6415 (23.2) | 1 357 080 (20.5) |
| 50-64 | 7590 (27.5) | 2 473 900 (37.3) |
| Race | ||
| White | 17 110 (62.0) | 5 308 180 (80.0) |
| African American | 8725 (31.6) | 739 210 (11.1) |
| Other | 1780 (6.4) | 586 360 (8.8) |
| Obese (BMI≥30.0) | 19 730 (71.4) | 2 897 890 (43.7) |
| Tobacco smoker | 15 680 (56.8) | 2 250 810 (33.9) |
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); HS, hidradenitis suppurativa.
Percentages have been rounded and may not total 100.
Discussion
Patients in the United States with HS are more likely to have low SES compared with patients without HS. However, the strength of association in our analysis is highly attenuated after accounting for relevant covariates, including age, sex, obesity, tobacco smoking, and race/ethnicity.
In a Dutch cohort analysis3 that included approximately 1018 patients with HS, lower SES, as determined by zip code analysis of mean household income and real estate values, was significantly more frequent among the patients with HS compared with an age- and sex-matched reference group (46.4% vs 34.3%; P < .001). However, the primary analysis in this study did not account for important covariates such as obesity, smoking status, and race, which in the United States may be associated with HS as well as the outcome of low SES.4,5,6
We were unable to evaluate educational attainment or employment status within the framework of this database. We also could not determine directionality between HS and SES in this analysis. However, we speculate that the modest association of HS with low SES shown in this analysis is a consequence of the quality-of-life effects (ie, symptoms including pain and malodorous discharge) of HS, and that low SES may not be a driver for the development of HS. Nonetheless, we suggest an attentive awareness to the potential for disparate outcomes among patients with HS who have low SES.
References
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