Investigating the risk of Incident diabetes mellitus among primary care patients treated with simvastatin in North-Central Trinidad.

Abstract

To determine the risk of new-onset diabetes mellitus in patients treated with simvastatin at primary healthcare clinics in North Central Trinidad. A retrospective descriptive case-series study design was applied to 384 conveniently sampled patient medical records from the cluster of primary healthcare centers during the period of February 2016-May 2016. Information from the patient files were then recorded using a systematic data extraction form. The major inclusion criteria were non-diabetic patients who were compliant with daily simvastatin for a minimum period of 1 year. The risk of incident diabetes mellitus was calculated, using SPSS version 20.0. Chi-squared (χ²) testing was performed to determine any association between new-onset diabetes mellitus and simvastatin use. In all, 207 patients became diabetic during their treatment period translating into a 53.9% risk of incident diabetes mellitus (χ² = 2.3438, <i>P</i> = 0.1258). A subgroup analysis of 133 subjects was performed to eliminate the confounders of family history of diabetes and age greater than 60 years. In this subgroup, 50 incident diabetics (37%) were identified and a statistically significant association was observed (χ² = 8.118, <i>P</i> = 0.0042). Linear regression revealed that this association was dose-dependent with a corresponding 32% higher risk in patients taking 40 mg (<i>P</i> = 0.001) of simvastatin daily compared with 20 mg of simvastatin (<i>P</i> = 0.094). Linear regression also revealed that there was significant statistical association between onset of diabetes mellitus and duration of statin therapy (<i>P</i> = 0.006). In this population, simvastatin use is associated with a 53.9% increased risk of development of new-onset diabetes mellitus (χ² = 2.3438, <i>P</i> = 0.1258). A statistically significant association was attained after subgroup analysis involving patients less than 60 years old and without a family history of diabetes with an incident risk of 37%. The increased risk of incident diabetes mellitus conferred by higher doses of simvastatin warrants consideration by physicians considering therapies for dyslipidemia in patients with multiple risk factors for diabetes mellitus.