American Spending on Diuretics Directly Predicts End-Stage Renal Failure Incidence Changes in a Time-Lagged Fashion

Abstract

<h3>Background</h3> We have previously reported a direct association between diuretic use in the United States and the incidence behavior of renal failure. The previous reports were based upon observed percentage changes in spending on diuretic therapy, assumed to reflect changes in global diuretic consumption, and percentage changes in the annual incident rate of renal failure. This report is intended to simplify the previously identified relationship by correlating the annual percent changes in renal failure incidence with the total annual expenditure for diuretics in the United States (in $US). <h3>Methods</h3> Renal failure rates as reported by the United States Renal Data Service (USRDS) were analyzed. Annual changes in incidence were expressed as percent changes. IMS Health reports total American spending on diuretics in US dollars. These data were subjected to regression analysis. <h3>Results</h3> Linear regression analysis identifies a significant direct correlation existing between global US diuretic spending and the incidence rate changes for renal failure time-lagged 4 years later (r=0.74864, p=0.0319). Although a significant linear relationship can be demonstrated, further analysis demonstrates a significant departure from linearity requiring analysis of a curvilinear relationship. A second degree equation exists opening upwards (r=0.82354, p=0.0191) indicating that renal failure incidence rises as total diuretic spending in the United States rises, and that renal failure incidence rises more precipitously as total American diuretic expenditure rises above $535.6 Million. Analysis of year 1999 prescribing behavior demonstrates that of total prescriptions in the US for diuretics, 55% of prescriptions were for hydrochlorothiazide and 45% were for loop diuretics, predominantly furosemide. While HCTZ accounted for 55% of diuretic prescriptions in 1999, it accounted for only 45% of total diuretic expenditure. Analysis of year 2000 prescriptions of new medications identifies that 55% of new diuretic prescriptions that year were for hydrochlorothiazide and 45% were for loop diuretics. Conclusions: Changes in renal failure incidence in the United States directly correlate to global American spending on diuretic therapy, time-lagged by 4 years. The predominant diuretic prescribed in the United States during the time frame of this analysis was hydrochlorothiazide. Recent reports suggest that new diuretic prescriptions have expanded by over 20% abruptly following the report of the ALLHAT trial findings. This analysis suggests that a dramatic increase in renal failure incidence in 2007 will be the result of this altered prescribing behavior.