Background:

No abstract

Background Allopurinol reduces oxidative stress and interacts with purinergic signalling systems important in bone metabolism and muscle function. We assessed whether allopurinol use was associated with a reduced incidence of hip fracture in older people who had undergone rehabilitation. Methods Analysis of prospective, routinely-collected rehabilitation and hospitalisation data. Data on patients discharged from a single inpatient geriatric rehabilitation centre over a 12 year period were linked to community prescribing data and ICD-10 coded hospitalisation data. Exposure to allopurinol was derived from prescribing data, and hip fracture was derived from hospitalisation data. Time-dependent covariate analysis was used to model time to hip fracture, incorporating ever-use of allopurinol, cumulative exposure to allopurinol, and covariates (age, sex, Barthel Index, comorbid disease, concomitant medication and biochemistry indices) Results 3517 patients were alive at discharge from rehabilitation without a previous diagnosis of hip fracture; mean age 84 years. 1474 (39%) were male, and 253 (7%) had at least one exposure to allopurinol. A total of 313 (9%) sustained a hip fracture, and 2628 (75%) died during a mean follow up of 3.1 years. In fully adjusted analyses, each year of allopurinol exposure showed a hazard ratio of 0.17 (95%CI 0.01 to 2.70) for hip fracture, 1.22 (0.87 to 1.70) for death, and 1.14 (0.81 to 1.61) for time to death or hip fracture. Ever-use of allopurinol was associated with a hazard ratio of 1.48 (0.75 to 2.91) for hip fracture, 1.48 (1.16 to 1.90) for death and 1.49 (1.16 to 1.91) for death or hip fracture. Conclusion Allopurinol use may be a marker of increased risk of death and hip fracture, but greater cumulative exposure to allopurinol may be associated with a reduced risk of hip fracture. Studies with more events are required to confirm or refute these initial non-significant findings.

No abstract