Objective-The purpose of this study was to compare the long term eVectiveness between chloroquine (CQ) and hydroxychloroquine (HCQ). Methods-Medical charts of all patients seen by eight rheumatologists practising in two tertiary care centres and starting antimalarial treatment between January 1985 and December 1993 were reviewed. Patient characteristics, 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 ineYcacy, or both. Bivariate analysis including t tests and 2 tests were used to assess diVerences between means and proportions respectively. Survival curves were evaluated using the Kaplan-Meier method. Multivariate analysis (Cox regression) was used to adjust for potential confounders. Results-After all medical records were reviewed, 1042 eligible cases were identified. From these, 940 (90%) had usable information and they represent the cohort. Five hundred and fifty eight had rheumatoid arthritis, 178 had systemic lupus erythematosus, 127 had palindromic arthritis, and 77 had other diagnoses. Fifty seven per cent of the patients received CQ and 43% HCQ. The proportion of patients with side eVects taking HCQ and CQ was 15% and 28% respectively (p=0.001). Using Cox regression model to adjust for age at the onset of antimalarial treatment, physician diVerences, sex, disease type, disease duration before treatment, and rank selection, there were no diVerences in the hazard ratio (HR) for overall discontinuations between 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 discontinuations because of ineYcacy 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 eVective than CQ. Only one case of probable/possible retinopathy was found. Therefore, we propose a careful baseline ophthalmological evaluation by an expert and then one or every two years if proper doses are used.

Our results are consistent with previous estimates and other North American findings, and provide results from coast to coast, as well as useful information about the degree of regional and demographic variations that can be seen within a single country. Our work demonstrates the usefulness of using multiple data sources, adjusting for the error in each, and providing estimates of the sensitivity of different case definition approaches.

The purpose of this study was to compare the long-term effectiveness among danazol, corticosteroids, cytotoxics, and dapsone in the treatment of hematological manifestations of systemic lupus erythematosus (SLE). Medical charts of all patients seen at the Rheumatic Disease Unit from January to December of 1998 were reviewed. Patient characteristics, disease and treatment information were collected. The main outcome measures were the cause of and time to discontinuation of drugs used to treat hematological manifestations of SLE resulting from all causes, mainly toxicity and inefficacy or both. Bivariate analysis including one-way ANOVA and chi2 tests were used to compare differences between means and proportions, respectively. Survival curves among the different drugs were evaluated using the Kaplan-Meier method. Multivariate analysis (Cox-regression) was used to adjust for potential confounders. After all medical records were reviewed 41 cases were eligible. Two cases had hemolytic anemia, 34 had thrombocytopenia, and five had both. These cases had received a total of 121 cycles of treatment at different times and they represent the study population (corticosteroids n = 37, danazol n = 51, citotoxic drugs n = 29, and dapsone n = 4). Crude rates of discontinuations due to any cause, toxicity and inefficacy werenot statistically significant among the drugs. However, the Kaplan-Meier curves showed statistically significant difference for discontinuations due to all causes as well as inefficacy. Prednisone and cytotoxic drugs had the lowest probability of continuation. In contrast, there were not statistically significant differences among the drugs with respect to first relapse. This is the first study examining the long-term termination rates of several drugs used to treat hematological manifestations of SLE. Using rates of discontinuation adjusted for time there were statistically significant differences among the drugs. Danazol had the highest probability of continuation.