Nephrotic proteinuria, kidney function deterioration tied to hypothyroidism

In patients with chronic kidney disease (CKD), nephrotic-range proteinuria and worsening kidney function are associated with hypothyroidism, a recent study has found.

Researchers conducted a cross-sectional study of 421 CKD patients (mean age 61 years, 55 percent men) who had undergone 24-hour urine protein (UP) excretion and thyroid function tests. Kidney function was expressed using 24-hour creatinine clearance (24hCcr), while nephrotic syndrome was defined as proteinuria >3.5 g/24 hours along with hypoalbuminemia <3.0 g/dL.

Multivariate logistic regression analysis revealed that worsening kidney function was a significant correlate for total hypothyroidism. Each 10-mL/min decrease in 24hCcr was associated with a nearly 30-percent increase in the odds of hypothyroidism (odds ratio [OR], 1.29, 95 percent confidence interval [CI], 1.18–1.41).

Meanwhile, nephrotic syndrome increased the likelihood of hypothyroidism by nearly 250 percent (OR, 2.49, 95 percent CI, 1.28–4.84).

Participants were then divided into four UP subgroups: <0.5, 0.5–1.49, 1.5–3.49, and ≥3.5 g/day. Nominal logistic regression showed that total hypothyroidism was significantly more likely to develop in the highest vs lowest category (OR, 1.95, 95 percent CI, 1.06–3.59). No such effect was reported for the second and third groups.

“Appropriate analysis of thyroid function and appropriate treatment for hypothyroidism in CKD patients are recommended to slow the progression of CKD, and at least a routine analysis of thyroid function in CKD patients with decreased kidney function or nephrotic range proteinuria would be recommended,” the researchers said.