Liver function testing in patients on HMG-CoA reductase inhibitors.

Abstract

The Food and Drug Administration currently requires the labeling of HMG-CoA reductase inhibitors to recommend liver function tests (LFTs) before the start of therapy and at various intervals during therapy, depending on the specific agent. We sought to determine the frequency and patterns of LFT screening in patients receiving HMG-CoA reductase inhibitors. A retrospective study was conducted at a staff-model health maintenance organization among 4178 new users of HMG-CoA reductase inhibitors during the period 1 January 1991 through 31 December 1996. The number and proportions of HMG-CoA reductase inhibitor therapy courses with baseline LFTs (within 180 days prior to dispensing), follow-up LFTs and LFT abnormalities were calculated. For the initial HMG-CoA reductase inhibitor dispensed, 1947 patients (47%) had at least one screening LFT at baseline and 3063 (73%) had at least one follow-up LFT. Twenty-seven (0.9%) patients with at least one follow-up LFT performed had a level greater than 3 times the upper limit of normal. In a random sample of 100 discontinued patients, none discontinued due to elevated LFTs or liver disease. A large proportion of patients dispensed HMG-CoA reductase inhibitors in this managed care setting did not have baseline and follow-up LFTs performed. Modest LFT abnormalities were common among users of HMG-CoA reductase inhibitors; however, in this population, serious abnormalities were rare.