Stopping smoking slows accelerated progression of renal failure in primary renal disease

BACKGROUND: Cigarette smoking accelerates the progression of renal failure in primary kidney diseases. It is not known, however, whether stopping smoking slows this accelerated loss of renal function. METHODS: 45 patients with progressive primary nephropathies (glomerulonephritis or tubulointerstitial nephritis) and moderate renal failure were encouraged to stop heavy cigarette smoking (1-2 packs per day); 26 patients refused to change their smoking habits (current smokers), and 16 successfully stopped (ex-smokers) during the 24 month study period. Carboxyhemoglobin and creatinine clearance were measured every six months. The primary end-point of the study was end-stage renal disease requiring renal replacement therapy. RESULTS: There were no significant differences between the two patient groups in demographic, renal and treatment characteristics at the start of the study. Current and ex-smokers had similar rates of decline of creatinine clearance during the 24 months before the investigations. Compared to ex-smokers or matched non-smoking renal patients, permanent smokers had a significantly faster decline in creatinine clearance during the two-year study period. Renal replacement therapy had to be started in six smokers, but only in one ex-smoker and none of the non-smokers during the study period. CONCLUSIONS: Giving up smoking slowed the rapid progression of renal failure, but did not reverse the loss of renal function induced by smoking. We recommend that increased efforts should be made to encourage renal patients to give up smoking in order to prolong dialysis-free kidney survival.