Patient-reported gout attack frequency and allopurinol use in general practice in the Netherlands: a prospective observational cohort study protocol.

INTRODUCTION: Gout is the most common inflammatory arthritis in the Dutch general practice population and is often managed with long-term uric acid lowering treatment. The clinical relevance of this treatment in preventing gout attacks is unclear. PRIMARY RESEARCH QUESTION: What is the frequency of self-reported gout attacks and what is the effect of allopurinol use in patients diagnosed with gout in general practice? METHODS AND ANALYSIS: Adult patients with a diagnostic consultation code for gout in the year 2013, 2014 or 2015 will be invited to participate in this prospective observational cohort study. Patients with a limited life expectancy will be excluded. Baseline measurements will include blood pressure, body mass index and a blood sample (estimated glomerular filtration rate, serum uric acid, cholesterol (low-density lipoprotein (LDL) and high-density lipoprotein), glucose (fasting)). At the 2-year follow-up, patients will receive questionnaires every 3 months. The questionnaires at baseline, 12 months and 24 months assess the frequency of gout attacks, the presence of tophi, comorbidity, medication use, quality of life, diet and lifestyle. The questionnaires in between only assess the frequency of gout attacks and medication use for gout. Descriptive statistics will be used to calculate the mean frequency of self-reported gout attacks during the 2-year follow-up. The propensity score for each patient being offered allopurinol is estimated and used to match patients with and without allopurinol treatment. We will compare the frequency of gout attacks in these groups using multilevel Poisson regression analyses. With this type of analysis, we can calculate the corrected estimated effect of allopurinol on gout attack frequency. ETHICS AND DISSEMINATION: The research protocol was approved by the Medical Ethical Committee of the Erasmus Medical Centre in Rotterdam. The knowledge generated by this study will be transferred to the Dutch College of General Practitioners, conferences and to (inter)national peer-reviewed journals. TRIAL REGISTRATION NUMBER: NTR6329; Pre-results.

The Effect of Prolonged Glucosamine Usage on HbA1c Levels and New-Onset Diabetes Mellitus in Overweight and Obese Middle-Aged Women.

OBJECTIVE: The aim of the present study was to evaluate the effect of a 2.5-year glucosamine sulfate intervention on hemoglobin A1c (HbA1c) levels and the incidence of new-onset diabetes mellitus over 6.5 years in middle-aged women with a body mass index ≥27 kg/m2. METHODS: In total, 407 women were randomized into either oral crystalline glucosamine sulfate or placebo. At baseline, 1 year, 2.5 years, and 6.5 years, a blood sample for the HbA1c level was drawn and questionnaires were taken. After 6.5 years there were missing data for some variables, therefore, multiple imputation was used. With the imputed data, a generalized estimating equation was performed to analyze the effect of glucosamine sulfate usage over 6.5 years. Finally, these analyses were rerun for the 2 subgroups of participants with and without high HbA1c level (≥42 mmol/mol) at baseline. RESULTS: There was no significant effect of a 2.5-year glucosamine sulfate intervention on mean HbA1c level or on obtaining a high HbA1c level or new-onset diabetes mellitus over 6.5 years. The subgroup analyses of participants with and without high HbA1c level at baseline were also not statistically significant. However, participants with a high HbA1c level at baseline had higher odds ratios compared with the participants with a normal HbA1c at baseline. CONCLUSIONS: There was no effect of glucosamine sulfate on mean HbA1c level nor on obtaining a high HbA1c level or new-onset diabetes mellitus over 6.5 years, especially in participants with a normal HbA1c level at baseline.