Latitude gradient influences the age of onset in rheumatoid arthritis patients.

The mean age of rheumatoid arthritis (RA) onset is around 50 years as reported in several clinical trials involving Caucasian patients. However, clinical observations suggest that Mexican RA patients' disease is initiated at a younger age. The objective of the study was to assess whether the age of onset of RA is different in Mexican and in Canadian RA patients. Certified rheumatologists from Canada and Mexico directly interviewed consecutive RA patients attending their clinics regarding the date patients first noticed a swollen joint. None of the participant rheumatologists were aware of the primary aim of this exploratory study at the time of the interviews. Data was gathered from 161 Mexican (91% women) and 130 Canadian (77% women) RA patients collected by three rheumatologists in each country. Duration since disease onset was not different within countries (mean 95% confidence interval [CI] for differences -10 to 16 years, p = 0.12 for Canadians, and -6 to 10 years, p = 0.26, for Mexicans). However, there was a significant difference between the two countries. Mexicans patients on average developed RA almost 12 years younger than Canadians (95% CI for difference 9 to 15 years, p < 0.001). Frequency distribution showed that 35.5% of Canadians but only 4% of Mexicans had the onset of the disease after the age of 55 (all p < 0.001). It appears that RA begins at a much younger age in Mexican than Canadian patients. If this were confirmed after controlling for different confounders and biases, it would have important societal, economic, and therapeutic implications.

A six-month randomized, controlled, double-blind, dose-response comparison of intravenous pamidronate (60 mg versus 10 mg) in the treatment of nonsteroidal antiinflammatory drug-refractory ankylosing spondylitis.

OBJECTIVE: To determine the safety and efficacy of intravenous (IV) pamidronate treatment in ankylosing spondylitis (AS) patients who have had a suboptimal response to nonsteroidal antiinflammatory drugs (NSAIDs). METHODS: Pamidronate at 60 mg was compared with pamidronate at 10 mg rather than placebo in view of the high incidence of transient arthralgias upon first IV exposure to the drug. The drug were given monthly for 6 months in a randomized double-blind, controlled trial. The inclusion criterion was active disease (Bath AS Disease Activity Index [BASDAI] of > or = 4 or morning stiffness of > or = 45 minutes) despite stable NSAID therapy. The primary outcome measure was the BASDAI, and secondary outcomes included the Bath AS Functional Index (BASFI), Bath AS Global Index (BASGI), Bath AS Metrology Index (BASMI), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level, and percentage of patients achieving a reduction of > or = 25% in the BASDAI. Outcome assessments were done at -2, 0, 12, and 24 weeks, and analysis was by intent to treat. RESULTS: Eighty-four AS patients (67 men and 17 women; mean age 39.6 years and mean disease duration 15.1 years) were enrolled. Dosage groups were well matched at baseline for demographics, disease activity, and functional indices. At 6 months, the mean BASDAI had decreased by 2.22 (34.5%) in the 60-mg group and by 0.93 (15%) in the 10-mg group (P = 0.002). Significantly greater reductions in the 60-mg group were also noted for the BASFI (P < 0.001), BASGI (P = 0.01), and BASMI (P = 0.03). Significantly more patients achieved a reduction of > or = 25% in the BASDAI in the 60-mg group versus the 10-mg group (63.4% versus 30.2%; P = 0.004). Differences in ESR/CRP were not significant (NS). Withdrawals included 9 (20.9%) from the 10-mg group and 3 (7.3%) from the 60-mg group (P NS). Adverse events were confined to transient arthralgias/myalgias after the first IV infusion, occurring in 68.3% and 46.5% of patients in the 60-mg and 10-mg groups, respectively (P NS). CONCLUSION: Pamidronate has dose-dependent therapeutic properties in AS.