PSY32 - CLAIMS-BASED ANALYSIS OF HOMOCYSTEINE TESTING, ELEVATED HOMOCYSTEINE LEVELS, AND HOMOCYSTINURIA DIAGNOSIS IN THE U.S.

Abstract

Approximately 1 in 200,000–335,000 people worldwide have homocystinuria (HCU) but it may be underdiagnosed. We examined incidence and prevalence of homocysteine (tHcy) testing and the frequency of tHcy levels >30 μmoles/L. In the MarketScan© Lab Database (MSN), we identified commercially insured patients with claims for a tHcy test (1/1/2006–3/31/2016). Frequency of elevated tHcy test result >30 μmoles/L and medications prescribed were examined. Frequencies of select comorbidities were assessed, using International Classification of Diseases (ICD-9 and ICD10) codes. Incidence of first-time tHcy testing and incidence and prevalence of tHcy >30 μmoles/L were tabulated. Of 8.2 million MSN patients in the Lab database, 1.9 million were enrolled throughout 4/1/15–3/31/16. Of those, 0.8% (15,012) had a tHcy test since 2006 (mean±SD, 10.8 ±15.1 μmoles/L). Of the 15,012 patients, 223 (1.5%) had tHcy >30 (96.0±174.1, median 39.9). Of the 223, 45% were diagnosed with hypertension, 44% hyperlipidemia, 17% hypothyroidism, 15% vitamin D deficiency and 12% renal disease, with only 10% (22) diagnosed with HCU or a sulfur amino acid metabolism disorder. After a tHcy >30 result, 11% were prescribed antihypertensives, 10% lipid-lowering drugs, 9% anxiolytics or antidepressants, 7% thyroid hormone and 2% vitamin D. Annual incidence of a first tHcy test result was 0.8–2.3 (mean 1.5) tests/1000 person years in 2009–2015. The incidence of a first tHcy result >30 was 0.01–0.06 (mean 0.03)/1000. Estimated point prevalence of tHcy >30 in the U.S. on 4/1/2016 was ∼0.010%– 0.014% (33,562–43,706). This study is one of the first to estimate the prevalence of tHcy levels in the range of classical HCU in the U.S. Of patients having many symptoms associated with classical HCU, few were diagnosed with a sulfur metabolism disorder. Such patients warrant further evaluation for etiology of their hyperhomocysteinemia, including screening for classical HCU.