Ja. Avinazubieta et al., LONG-TERM EFFECTIVENESS OF ANTIMALARIAL-DRUGS IN RHEUMATIC DISEASES, Annals of the Rheumatic Diseases, 57(10), 1998, pp. 582-587
Objective-The purpose of this study was to compare the long term effec
tiveness between chloroquine (CQ) and hydroxychloroquine (HCQ). Method
s - Medical charts of all patients seen by eight rheumatologists pract
ising in two tertiary care centres and starting antimalarial treatment
between January 1985 and December 1993 were reviewed. Patient charact
eristics, disease, and treatment information were collected. The main
outcome measures were the cause of and the time to the discontinuation
of antimalarial drugs resulting from all causes, principally toxicity
or inefficacy, or both. Bivariate analysis including t tests and chi(
2) tests were used to assess differences between means and proportions
respectively. Survival curves were evaluated using the Kaplan-Meier m
ethod. Multivariate analysis (Cox regression) was used to adjust for p
otential confounders. Results - After all medical records were reviewe
d, 1042 eligible cases were identified. From these, 940 (90%) had usab
le information and they represent the cohort. Five hundred and fifty e
ight had rheumatoid arthritis, 178 had systemic lupus erythematosus, 1
27 had palindromic arthritis, and 77 had other diagnoses. Fifty seven
per cent of the patients received CQ and 43% HCQ. The proportion of pa
tients with side effects taking HCQ and CQ was 15% and 28% respectivel
y (p = 0.001). Using Cox regression model to adjust for age at the ons
et of antimalarial treatment, physician differences, sex, disease type
, disease duration before treatment, and rank selection, there were no
differences in the hazard ratio (HR) for overall discontinuations bet
ween CQ and HCQ. While the HR for discontinuations because of toxicity
was lower for HCQ (HR = 0.6, 95% CI 0.4, 0.9), the HR for discontinua
tions because of inefficacy was significantly higher for HCQ (HR = 1.4
, 95% CI 1.1, 1.9). Conclusions - After adjusting for time and several
confounders HCQ was less toxic but less effective than CQ. Only one c
ase of probable/possible retinopathy was found. Therefore, we propose
a careful baseline ophthalmological evaluation by an expert and then o
ne or every two years if proper doses are used.