Do selected drugs increase the risk of lupus? A matched case-control study.
OBJECTIVE
To investigate the association between risk of lupus and exposure to selected drugs implicated in risk of lupus in a number of case reports.


METHODS
In this matched nested case-control study we utilized primary care data from the UK General Practice Research Database recorded between 1987 and 2001. Cases with at least one medical code for systemic lupus erythematosus or drug-induced lupus in their computerized records were matched to controls without a medical code for lupus or any other autoimmune disorder. Using conditional logistic regression we computed odds ratios (OR) and 95% confidence intervals (CI) for risk of lupus associated with exposure to selected drugs.


RESULTS
There were 875 incident cases, of which 12% (n= 107) had evidence of a prescription for one or more of the suspected drugs, and 3632 matched controls. For some drugs, prescriptions were too uncommon to be able to estimate associated risk of lupus. Despite small numbers of exposed patients and low statistical precision we observed an increased risk of lupus for hydralazine (OR = 6.62, 95% CI 1.03, 42.74), minocycline (OR = 4.23, 95% CI 2.65, 6.75) and carbamazepine (OR = 1.88, 95% CI 1.09, 3.22). There was some indication that the effect of carbamazepine was restricted to women (P for interaction by gender = 0.047).


CONCLUSIONS
This study shows that even those drugs suggested by case reports as causing lupus cannot all be clearly shown to be associated, even in a very large population-based database. Our findings support causal relationships for carbamazepine, minocycline and possibly hydralazine. Overall, drugs do not seem to be a major cause of lupus.
Schoonen
W Marieke
WM
Department of International Epidemiology, Amgen Ltd, Uxbridge Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom.
Thomas
Sara L
SL
Somers
Emily C
EC
Smeeth
Liam
L
Kim
Joseph
J
Evans
Stephen
S
Hall
Andrew J
AJ
D000328:Adult; D000889:Anti-Arrhythmia Agents / Q000009:adverse effects; D000900:Anti-Bacterial Agents / Q000009:adverse effects; D000927:Anticonvulsants / Q000009:adverse effects; D000959:Antihypertensive Agents / Q000009:adverse effects; D014150:Antipsychotic Agents / Q000009:adverse effects; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008178:Lupus Erythematosus, Cutaneous / Q000139:chemically induced* / Q000453:epidemiology; D008180:Lupus Erythematosus, Systemic / Q000139:chemically induced* / Q000453:epidemiology; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D055553:Prescription Drugs / Q000009:adverse effects*; D012306:Risk; D012737:Sex Factors; D014665:Vasodilator Agents / Q000009:adverse effects
D000889:Anti-Arrhythmia Agents; D000900:Anti-Bacterial Agents; D000927:Anticonvulsants; D000959:Antihypertensive Agents; D014150:Antipsychotic Agents; D055553:Prescription Drugs; D014665:Vasodilator Agents