Orthostatic changes in blood pressure and mortality in a nursing home population

Objective: Hypertension, orthostatic hypotension and orthostatic hypertension (OHT) are highly prevalent in old age. The associations in the very elderly and frail patients between blood pressure, and especially orthostatic changes in blood pressure, and mortality are unclear. We aimed to investigate the relationships between orthostatic changes in blood pressure, blood pressure and mortality in nursing home residents. Design and methods: A prospective observational cohort study. Cox proportional hazard modelling was used to investigate the relation between orthostatic hypotension, OHT, the various blood pressure variables and mortality with adjustment for confounders. In the case of significant associations in the models, risk prediction capabilities were assessed with Harrell's C statistics and the proportion of explained variance (R-2). Results: Two hundred and ninety patients with a mean age of 80.8 (SD 9.9) years participated in this study. The overall mortality risk increased by 17% [95% confidence interval (CI): 2-34%] for every 10-mmHg increase in DBP. Adding DBP did not change Harrell's C values and increased R-2 with 0.03 or less. Only in patients at the psychogeriatric department, orthostatic hypotension was associated with an increased all-cause mortality risk [hazard ratio (HR) 1.71 (95% CI: 1.08-2.71%)]. The HR of OHT in this patient group was 0.61 (95% CI: 0.32-1.19%). Conclusion: DBP was related to all-cause mortality in a nursing home population. Orthostatic hypotension was related to all-cause mortality in the most frail group of nursing home patients. The predictive capabilities of both DBP and orthostatic hypotension are rather small with respect to mortality. A beneficial effect of OHT could not be excluded on the basis of the width of the CI.