Thiazides diuretics in the treatment of nephrolithiasis: are we using them in an evidence-based fashion?

Abstract

In the 1980s a change occurred in hydrochlorothiazide prescribing practices for hypertension from high-dose (50 mg/day) to low-dose (12.5-25 mg/day) therapy. However, randomized controlled trials (RCT) for prevention of calcium-containing kidney stones (CCKS) employed only high doses (≥ 50 mg/day). We hypothesized that these practices have resulted in underdosing of hydrochlorothiazide for prevention of CCKS. Patients with a filled prescription for thiazide diuretics that underwent a 24-h urine stone risk factor analysis were eligible. Those with evidence that thiazide was prescribed for CCKS were further analyzed. Of 107 patients, 102 were treated with hydrochlorothiazide, 4 with indapamide, and one with chlorthalidone. Only 35% of hydrochlorothiazide-treated patients received 50 mg/day; a dose previously shown to reduce stone recurrence. Fifty-two percent were prescribed 25 mg and 13% 12.5 mg daily, doses that were not studied in RCT. Evidence-based hydrochlorothiazide use was suboptimal regardless of where the patient received care (Nephrology or Endocrinology clinic). In a small subset of patients (n = 6) with 24-h urinary calcium excretion measured at baseline and after 2 hydrochlorothiazide doses (25 and ≥ 50 mg), there was a trend toward decreased urinary calcium excretion as the dose was increased from 25 to ≥ 50 mg/day (p = 0.051). Low-dose hydrochlorothiazide was often used for prevention of CCKS despite the fact that there is no evidence that it is effective in this setting. This may have resulted from a practice pattern of using lower doses for hypertension therapy or a lack of knowledge of RCT results in treatment of CCKS.

• Authors: Rebecca Vigen, Rick A Weideman, Robert F Reilly
• Journal: International urology and nephrology (Int Urol Nephrol) Vol. 43 Issue 3 Pg. 813-9 (Sep 2011) ISSN: 1573-2584 [Electronic] Netherlands
• PMID: 20737209 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Sodium Chloride Symporter Inhibitors
• Hydrochlorothiazide
• Indapamide
• Chlorthalidone

Topics

• Adult
• Aged
• Aged, 80 and over
• Analysis of Variance
• Chi-Square Distribution
• Chlorthalidone (administration & dosage, therapeutic use)
• Dose-Response Relationship, Drug
• Evidence-Based Medicine
• Female
• Humans
• Hydrochlorothiazide (administration & dosage, therapeutic use)
• Indapamide (administration & dosage, therapeutic use)
• Kidney Calculi (prevention & control)
• Male
• Middle Aged
• Practice Patterns, Physicians'
• Sodium Chloride Symporter Inhibitors (administration & dosage, therapeutic use)