Introduction: osteoporosis is a common disease, and the incidence of osteoporotic fractures is expected to rise with the growing elderly population. Immediately following, and probably several years after a hip fracture, patients, both men and women, have a higher risk of dying compared to the general population regardless of age. The aim of this study was to assess excess mortality following hip fracture and, if possible, identify reasons for the difference between mortality for the two genders.

Methods: this is a nationwide register-based cohort study presenting data from the National Hospital Discharge Register on mortality, comorbidity and medication for all Danish patients (more than 41,000 persons) experiencing a hip fracture between 1 January 1999 and 31 December 2002. Follow-up period was until 31 December 2005.

Results: we found a substantially higher mortality among male hip fracture patients than female hip fracture patients despite men being 4 years younger at the time of fracture. Both male and female hip fracture patients were found to have an excess mortality rate compared to the general population. The cumulative mortality at 12 months among hip fracture patients compared to the general population was 37.1% (9.9%) in men and 26.4% (9.3%) in women. In the first year, the risk of death significantly increased for women with increasing age (hazard ratio, HR: 1.06, 95% confidence interval, CI: 1.06-1.07), the number of comedications (HR 1.04, 95% CI 1.03-1.05) and the presence of specific Charlson index components and medications described below. For men, age (HR 1.07, 95% CI 1.07-1.08), number of comedications (HR 1.06, 95% CI 1.04-1.07) and presence of different specific Charlson index components and medications increased the risk. Long-term survival analyses revealed that excess mortality for men compared with women remained strongly significant (HR 1.70, 95% CI 1.65-1.75, P < 0.001), even when controlled for age, fracture site, the number of medications, exposure to drug classes A, C, D, G, J, M, N, P, S and for chronic comorbidities.

Conclusion: excess mortality among male patients cannot be explained by controlling for known comorbidity and medications. Besides gender, we found higher age and multimorbidity to be related to an increased risk of dying within the first year after fracture; acute complications might be one of the explanations. This study emphasises the need for particular rigorous postoperative diagnostic evaluation and treatment of comorbid conditions in the male hip fracture patient.