A cost-minimization analysis of treatment options for postmenopausal women with dysuria

BACKGROUND: Empiric therapy for urinary tract infection is difficult in postmenopausal women because of the higher rates of confounding lower urinary tract symptoms and differential resistance profiles of uropathogens in this population. OBJECTIVE: The objective of the study was to determine the least costly strategy for treatment of postmenopausal women with the primary complaint of dysuria. STUDY DESIGN: We performed a cost minimization analysis modeling the following clinical options: (1) empiric antibiotic therapy followed by urine culture, (2) urinalysis with empiric antibiotic therapy only if positive nitrites and leukocyte esterase, or (3) waiting for culture prior to initiating antibiotics. For all strategies we included nitrofurantoin, trimethoprim/sulfamethoxazole, fosfomycin, ciprofloxacin, or cephalexin. Pathogens included Escherichia coli, Enterococcus faecalis, Klebsiella pneumonaie, or Proteus mirabalis. Pathogens, resistance, treatment success, and medication side effects were specific to postmenopausal women. RESULTS: Cost minimization modeling with TreeAge Pro assumed 73.4% of urinary tract infections were caused by Escherichia coli with 24.4% resistance to nitrofurantoin, trimethoprim/sulfamethoxazole. With our assumptions, empiric antibiotics with nitrofurantoin, trimethoprim/sulfamethoxazole was the least costly approach ($89.64/patient), followed by waiting for urine culture ($97.04/patient). Except for empiric antibiotics with fosfomcyin, empiric antibiotics was always less costly than using urinalysis to discriminate antibiotic use. This is due to the cost of urinalysis ($38.23), high rate of both urinary tract infection (91%), and positive urinalysis (69.3%) with dysuria in postmenopausal women and resultant high rate of antibiotic use with or without urinalysis. Options with fosfomycin were the most expensive because of the highest drug costs ($98/dose), and tornado analyses showed fosfomycin cost was the most impactful variable for model outcomes. Sensitivity analyses showed empiric fosfomycin became the least costly option if drug costs were $25.80, a price still more costly than almost all modeled baseline drug costs. This outcome was largely predicated on low resistance to fosfomycin. Conversely, ciprofloxacin was never the least costly option because of higher resistance and side effect cost, even if the drug cost was $0. We modeled 91% positive urine culture rate in postmenopausal women with dysuria; waiting for the urine culture prior to treatment would be the least costly strategy in a population with a predicted positive culture rate of <65%. CONCLUSION: The least costly strategy was empiric antibiotics with nitrofurantoin and trimethoprim/sulfamethoxazole, followed by waiting on culture results. Local resistance patterns will have an impact on cost minimization strategies. Empiric fosfomycin would be least costly with reduced drug costs, even at a level at which drug costs were higher than almost all other antibiotics. In a population with high posttest probability of positive urine culture, urinalysis adds unnecessary cost. Antibiotic stewardship programs should continue efforts to decrease fluoroquinolone use because of high resistance, side effects, and increased cost.