Vitamin D compounds for people with chronic kidney disease not requiring dialysis.
BACKGROUND
Vitamin D compounds are used to suppress elevated serum parathyroid hormone (PTH) in people with chronic kidney disease (CKD).


OBJECTIVE
To assess the efficacy of vitamin D therapy on biochemical, bone, cardiovascular, and mortality outcomes in people with CKD and not requiring dialysis.


METHODS
We searched The Cochrane Renal Group's specialised register, Cochrane's Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and reference lists of retrieved articles.


METHODS
Randomised controlled trials (RCTs) comparing different forms, schedules, or routes of administration of vitamin D compounds for people with CKD not requiring dialysis were included. Vitamin D compounds were defined as established (calcitriol, alfacalcidol, 24,25(OH)(2)vitamin D(3)) or newer (doxercalciferol, maxacalcitol, paricalcitol, falecalcitriol) vitamin D compounds.


METHODS
Data were extracted by two authors. Statistical analyses were performed using the random effects model. Results were summarized as risk ratio (RR) for dichotomous outcomes or mean differences (MD) for continuous outcomes with 95% confidence intervals (CI).


RESULTS
Sixteen studies (894 patients) were included. No formulation, route, or schedule of vitamin D compound was found to alter the mortality risk or need for dialysis. Vitamin D compounds significantly lowered serum PTH (4 studies, 153 patients: MD -49.34 pg/mL, 95% CI -85.70 to -12.97 (-5.6 pmol/L, 95% CI -9.77 to -1.48)) and were more likely to reduce serum PTH > 30% from baseline value (264 patients: RR 7.87, 95% CI 4.87 to 12.73). Vitamin D treatment was associated with increased end of treatment serum phosphorus (3 studies, 140 patients: MD 0.37 mg/dL, 95% CI 0.09, 0.66 (0.12 mmol/L, 95% CI 0.03, 0.21)) and serum calcium (5 studies, 184 patients: MD 0.20 mg/dL, 95% CI 0.17 to 0.23 (0.05 mmol/L, 95% CI 0.04 to 0.06)). Few data were available comparing intermittent with daily vitamin D administration, or other schedules of dosing.


CONCLUSIONS
There are not sufficient data to determine the effect of vitamin D compounds on mortality and cardiovascular outcomes in people with CKD not requiring dialysis. While vitamin D compounds reduce serum PTH (49.3 pg/mL (5.6 pmol/L)) compared with placebo, the relative clinical benefits of PTH lowering versus treatment-related increases in serum phosphorus and calcium remain to be understood.
Palmer
Suetonia C
SC
Renal Division, Brigham and Women's Hospital, Harvard Medical School, Harvard Institute of Medicine, Room 550, 4 Blackfan Street, Boston, MA, USA, 02115.
McGregor
David O
DO
Craig
Jonathan C
JC
Elder
Grahame
G
Macaskill
Petra
P
Strippoli
Giovanni Fm
GF
D050071:Bone Density Conservation Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001851:Bone Diseases, Metabolic / Q000097:blood / Q000209:etiology / Q000517:prevention & control; D002118:Calcium / Q000097:blood*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000401:mortality; D010281:Parathyroid Hormone / Q000097:blood*; D010758:Phosphorus / Q000097:blood; D016032:Randomized Controlled Trials as Topic; D006435:Renal Dialysis; D014807:Vitamin D / Q000031:analogs & derivatives*
D050071:Bone Density Conservation Agents; D010281:Parathyroid Hormone; D014807:Vitamin D; D010758:Phosphorus; D002118:Calcium