[Prevalence and risk factors of drug induced liver disease: a survey based study in pharmacies]

The reported incidence of drug-induced liver injury (DILI) ranges from 1 in 10,000 to 1 in 100,000 patients for most drugs, but the true incidence is expected to be much higher. Several risk factors for DILI susceptibility have been suggested, however there is insufficient data to define an individual risk profile. Therefore it was our aim to study the prevalence of DILI and potential risk factors within adult pharmacy customers in Germany.

We conducted two 6 week-survey studies in 30 pharmacies in 2011 and 2012, respectively, using a newly developed questionnaire comprising questions on demography, (liver) diseases, liver enzyme activities, and drug history. In each study, anonymized questionnaires were presented to non-selected adult customers taking (non-)prescription drugs.

Combining the datasets from the 2011 and 2012 surveys, in total 1098 questionnaires were evaluated (mean age 57.7 ± 17.1 years; 62.6 % females, return rate 15.25 %). Overall, 141 individuals (12.8 %) reported elevated liver enzymes due to drugs, in 65 cases (5.9 %) the medication had to be stopped, and 20 customers (1.8 %) reported that they had been admitted to hospital due to DILI. Compared to individuals without adverse hepatic drug reactions (n = 957), the 141 persons with potential DILI presented more often the following risk factors in multivariate analysis: chronic liver disease (14.4 % vs. 2.4 %, odds ratio [OR] 4.2, 95 % confidence interval [CI] 2.0 - 9.0), chronic renal insufficiency (20.0 vs. 6.8 %, OR 2.2, 95 % CI 1.3 - 3.7), diabetes (34 vs. 15.3 %, OR 2.0, 95 % CI 1.3 - 3.2), family history of chronic liver disease (19.9 vs. 7.7 %, OR 2.1, 95 % CI 1.2 - 3.6), and continuous drug intake for more than 5 years (80.9 vs. 59.3 %, OR 2.1, 95 % CI 1.3 - 3.5).

These studies show an unexpected high prevalence of DILI in pharmacy customers and identify multiple potential risk factors.