Upward trends in the incidence of neck of femur fractures in the elderly.

Aim: A recent paper by Fielden and colleagues suggested the incidence of neck of femur fractures among those aged 65 years and older underwent a much smaller increase during the 1990s than had previously been predicted. Given the importance of neck of femur fractures in New Zealand we sought to re-examine the conclusions of Fielden and colleagues, paying close attention to case selection.

Methods: Cases were selected from patients discharged by New Zealand public hospitals, with close attention paid to the inclusion criteria. Readmissions and day patients were excluded.

Results: Twenty eight per cent of the cases we identified were excluded as either readmissions or day patients. The resulting yearly incidence estimates were generally lower than those reported by Fielden and colleagues but the upward trends in incidence were stronger. Similarly, our estimates of the trends in age-specific rates for women showed the decline in these rates to be much less significant than that reported by Fielden and colleagues.

Conclusions: Age-group-specific rates of neck of femur fracture have not declined as much as Fielden and colleagues suggested. Case selection can have a significant effect on estimated incidence and trends derived from hospital data.