Lost to follow-up in high level evidence-based studies related to the surgical management of lower urinary tract symptoms secondary to benign prostatic enlargement: Does it matter?

Aims A contemporary review of the literature on benign prostatic hyperplasia (BPH) for lost to follow-up (LTF) rate was performed to evaluate the significance of LTF in the surgical management of lower urinary tract symptoms (LUTS) secondary to benign prostatic enlargement (BPE). Methods Randomized clinical trials (RCT level I) on the surgical treatment of LUTS secondary to BPE, with at least 12-month follow-up, from 1/1995 to 10/2010 were searched on PUBMED. Data reviewed included types of study, number of participating centers or hospitals, sample size calculation, surgical techniques, power calculation, estimated dropout rate, duration of follow-up, rate and reasons for LTF. Results Forty-eight RCT articles were identified. Eleven articles gave details on sample size calculation, and 13 explained their LTF rate after reaching LTF patients by mail or telephone. Percentages of LTF patients were 12% (492/4202) at 12 months in 39 articles, 21% (398/1891) at 24 months in 16 articles, 33% (485/1479) at 36 months in 11 articles, 41% (283/694) at 48 months in 6 articles, and 56% (409/729) at ≥60 months in 6 articles. Fifteen articles reported no missing data, mostly because of small sample size or short follow-up. Only 7 articles defined LTF patients as treatment failure and reported outcomes accordingly. Conclusions The increase in LTF rate over time compromises the strength of the conclusions from the leftover patient population. Only 15% of RCTs adhered to the CONSORT statement by considering their LTF patients as treatment failures.