The Effect of Vitamin D Treatment on Clinical and Biochemical Outcomes of Primary Aldosteronism

Noor Ashikin Ismail; Nor Azmi Kamaruddin; Shamsul Azhar Shah; Norlela Sukor

Disclosures

Clin Endocrinol. 2020;92(6):509-517. 

In This Article

Results

Two hundred and forty hypertensive patients who attended the Endocrine hypertension clinic from July till October 2018 were screened. Thirty-one patients had positive ARR, and 17 of them were further confirmed to have PA following SST or FST. One subject dropped out from the study following 1 week of treatment due to self-reported side effect (rashes) and not included in the follow-up analysis. The mean age of the subjects was 42 years old with 53% female. The mean age of hypertension detection was at 35 years old. Almost half of the subjects (47%) were on 3 antihypertensive medications. The commonest antihypertensive used was the nondihydropyridine group of CCB (94%). Half of the subjects (52%) were overweight and 24% obese (Table 1).

At baseline, more than half of the PA subjects (71%) were vitamin D insufficient whereas 29% have sufficient vitamin D level. Vitamin D deficiency is defined as concentration of less than 20 ng/mL, insufficient if the concentration is between 20 and 30 ng/mL and sufficient if the level is more than 30 ng/mL. At the end of the study, there was a significant 28% improvement in the overall 25(OH)D levels from baseline [mean 25(OH)D increment of 7.4 ng/mL, P < .001]. The proportion of patients with insufficient vitamin D levels were reduced by 30% by the end of the study (Figure 1). Among PA subjects with insufficient vitamin D levels at baseline, more than half of these individuals (55%) were able to achieve sufficient amount of vitamin D levels 3 months following treatment (Figure 2).

Figure 1.

Comparison of 25(OH)vitamin D levels at baseline and after treatment

Figure 2.

Percentage of 25(OH)vitamin D level increment after treatment

Clinical and biochemical parameters (Table 2) showed significant reduction in the SBP following treatment, (mean SBP reduction of 10 mm Hg, P = .01), and significant reduction in the PAC (mean PAC reduction of 63.3 pg/mL, P = .01) with 7.4 ng/mL increment in the vitamin D level. Concomitantly, there was significant improvement in the eGFR after treatment, with a mean eGFR increment of 8 mL/min/1.73 m2 (P = .02).

Further subgroup analysis as presented in Table 3 showed that the vitamin D deficient subgroup benefited the most with significant and greater magnitude in the systolic blood pressure reduction following treatment, with a mean SBP reduction of 18 mm Hg (P = .004) (Figure 3).

Figure 3.

Marginal means of systolic blood pressure reduction among the subject group

Pearson correlation coefficients of the SBP and vitamin D were −0.94 (P = .01) before treatment and −0.7 (P = .12) after treatment, indicating lower baseline vitamin D levels were associated with higher SBP. Furthermore, there was a significant correlation between plasma aldosterone concentration and the eGFR (r = −.95, P = .01) at baseline, indicating higher baseline aldosterone was strongly associated with lower eGFR. When further adjusting for the age and weight, the SBP difference after treatment remains statistically significant (P = .04). There were no other significant changes or association in the other biochemical parameters. No documented adverse event, hypercalcemia, hospitalization or vitamin D toxicity was observed throughout the study period.

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