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.