Age and gender standardised prevalence ratios (95% CI) comparing NorStOP responders at each survey point to CiPCA comparison population.

NorStOP = North Staffordshire Osteoarthritis Project; CiPCA = Consultations in Primary Care Archive; COPD = Chronic obstructive pulmonary disease; URTI = Upper respiratory tract infection; NSAID = Non-steroidal anti-inflammatory drug; CI = Confidence interval.For age and gender standardised prevalence ratios, the comparison population (CiPCA) = 1.00.a Consultation and prescriptions for the 2 years prior to baseline survey.b Consultation and prescriptions for the 2 years before 3-year follow-up survey.c Consultation and prescriptions for the 2 years before 6-year follow-up survey.