Orthostatic hypotension and vitamin D deficiency in older adults: systematic review and meta-analysis.

BACKGROUND

Over the latest years different studies have investigated the possible relationship between D deficiency and occurrence of orthostatic hypotension (OH), often reaching controversial results. We perform an update meta-analysis providing an update overview on the association between hypovitaminosis D and orthostatic hypotension (OH) in older adults.

METHODS

Data extraction was independently performed by two authors and based upon predefined criteria. The meta-analysis was performed using a random-effects model. Statistical heterogeneity between groups was measured using the Higgins I2 statistic.

RESULTS

Eight investigations enrolling 16.326 patients (mean age 75.5 years) met the inclusion criteria and were considered for the analysis. Patients with vitamin D deficiency were more likely to have OH compared to those without (OR: 1.36, 95% CI 1.14-1.63, p = 0.0001, I2 = 43.6%). A further sub-analysis, based on three studies, estimating the risk of OH in patients with hypovitaminosis D receiving antihypertensive treatment, did not reach the statistical significance (OR: 1.40, 95% CI 0.61-3.18, p = 0.418, I2 = 53.3%). Meta-regression performed using age (p = 0.12), BMI (p = 0.73) and gender (p = 0.62) as moderators did not reveal any statistical significance in influencing OH. Conversely, physical activity, Vitamin D supplementation and use of radioimmunoassay for the measurement of vitamin D serum levels showed a significant inverse relationship towards the risk of OH (Coeff.-0.09, p = 0.002, Coeff. - 0.12, p < 0.001 and Coeff. - 0.08, p = 0.03, respectively) among patients with hypovitaminosis D. A direct correlation between the administration of antihypertensive treatment and the risk of OH in older patients with low vitamin D level was observed (Coeff. 0.05, p < 0.001).

CONCLUSIONS

Hypovitaminosis D is significantly associated with OH in older adults and directly influence by the administration of antihypertensive drugs. Conversely, physical activity, vitamin D supplementation and use of radioimmunoassay as analytic method inversely correlated with the risk of OH in older patients.