The Prevalence and Regional Variation of Major Depressive Disorder Among Patients With Peripheral Arterial Disease in the Medicare Population

Abstract

Background: Current evidence suggests an association between coronary artery disease and major depressive disorder (MDD). Data to support a similar association between peripheral arterial disease (PAD) and MDD are more limited. This study examines the prevalence and regional variation of both PAD and MDD in a large contemporary patient sample. Methods: All Medicare claims, part A and B, from January 2009 until December 2011 were queried using diagnosis codes specific for a previously validated clinical algorithm for PAD and major depression. Codes for PAD included those specific to cerebrovascular disease, abdominal aortic aneurysm, and peripheral vascular disease. Peripheral arterial disease prevalence, major depression prevalence, and coprevalence rates were determined, respectively. Regional variation of both conditions was determined using zip code data to identify potential endemic areas of disease intensity for both diagnoses. Results: Over the study interval, the percentage of Medicare beneficiaries with a diagnosis of PAD remained relatively constant (3.0%-3.7%, n = 0.85-1.06 million in part A and 17.4%-17.5%, n = 4.82-4.93 million in part B), and MDD showed a similar trend (1.6%-2.7%, n = 0.46-0.79 million in part A and 6.1%-6.7%, n = 1.69-1.90 million in part B). The observed rate of MDD in those with an established diagnosis of PAD was 5-fold higher than those without PAD in part A claims (1.8-fold in part B claims). Moreover, there was a significant linear geographic correlation among patients with PAD and MDD ( r = .54, P ≤ .01). Conclusions: This study documents a correlation between PAD and MDD and may, therefore, identify an at-risk population susceptible to inferior clinical outcomes. Significant regional variation exists in the prevalence of PAD and MDD, though there appear to be specific endemic regions notable for both disorders. Accordingly, health-care resource allocation toward endemic regions may help improve population health among this at-risk cohort.