PREDICTION OF HIP FRACTURE IN ELDERLY WOMEN - A PROSPECTIVE-STUDY

Objective - To assess the relative importance of osteoporosis of the os calcis, cognisance, and mobility in the risk of subsequent fracture of the hip in elderly women. Design - Prospective study of elderly women in residential care over two years. Setting - 21 Private or 38 local authority residential homes for the elderly and 4 geriatric hospitals in Doncaster and Hull. Subjects - 1414 Ambulant women aged over 69, in private or local authority residential care or geriatric care. Those who had had bilateral hip surgery were excluded. Main outcome measures - Broad band ultrasonic attenuation (BUA) index, Clifton assessment procedures for the elderly test (for cognisance), and mobility on a six point scale, and fracture of the hip in the subsequent two year period. Results - 73 Women fractured their hip during the two years. Their mean age was not significantly different from that of the women who did not have a fracture (85.3 (SD 5.6) v 83.9 (6.3); p = 0.07), but their mean BUA index (40.3 (19.3) v 50.9 (22.2) db/MH2), and score for cognisance (median 19 (interquartile range 10.5-27.0) v 24 (17-30)) were significantly lower (both p < 0.001). These variables had independent associations with fracture of the hip. Women with fractures had a significantly lower score for the psychomotor component of the cognisance test (4.5 (1-8) v 7 (2-10); p < 0.0025 and were significantly more mobile (1(1-3) v 23 (1-6); p < 0.02). Subdividing women according to high, medium, and low scores for BUA index and cognisance testing disclosed a high risk group (118 women) with low BUA index and cognisance score, whose incidence of fracture was 12.8%; in the group at lowest risk (136 women) with high BUA index and cognisance score, the incidence of fracture was only 1.5% (relative risk 8.4 (95% confidence interval - 2.0 to 35.5)). Further analysis showed that those most at risk were, additionally, most mobile but that less mobile women with good cognisance had a low incidence of fractures, regardless of the BUA index, (1.2%, high index, v 0.9%, low index).