Association between adherence to folic acid supplements and serum folate, and plasma homocysteine among hemodialysis patients.

OBJECTIVE

To examine the relationship between adherence to prescribed folic acid supplements and folic acid intake, serum folate and plasma homocysteine in hemodialysis patients. The effects of change in adherence patterns from enrollment to 1 year later on changes in these same measures were also assessed.

DESIGN

Secondary data analysis.

PARTICIPANTS

Eighty-six hemodialysis patients who participated in the Hemodialysis (HEMO) Study's Homocysteine ancillary study.

MAIN OUTCOME MEASURES

Folic acid supplement intake, serum folate, and plasma homocysteine.

RESULTS

Eighty-eight percent of patients at enrollment and 91% 1 year later were adherent to prescribed folic acid supplements. Nonadherers had lower intakes of folic acid at both enrollment and 1 year later and lower serum folate levels at enrollment. Percent change was significantly different between the 3 adherence change groups for folic acid intake (P = .001) and plasma homocysteine (P < .001) from enrollment to 1 year later. The nonadherent group at enrollment had the lowest intakes and serum folate levels, and the highest plasma homocysteine levels. When they became adherent 1 year later, they had the greatest change in folic acid intake (5,461%; P = .03), coupled with a 69% increase in serum folate (P = .04) and a 29% decrease in plasma homocysteine (P = .03).

CONCLUSIONS

Hemodialysis patients who were nonadherent to folic acid supplement prescriptions had low folic acid intakes, low serum folates, and high homocysteine levels. When their adherence improved, folic acid intakes rose, serum folates increased, and plasma homocysteine levels decreased, although mild hyperhomocysteinemia persisted.