Table 4.

Diabetes mellitus and the prognosis of bladder cancer.

Study Author	Study Year	Total No. of Patients	Total No. of Studies	Study Type	Comments
Xu et al. [31]	2017	13,506,643	21	Meta-analysis of cohort studies	“The pooled analysis results for men indicated that the comparison of DM versus non-DM individuals showed a harmful effect (RR: 1.23; 95% CI: 1.06–1.42; p = 0.005, whereas there was no significant difference in women (RR: 1.24; 95% CI: 0.95–1.61; p = 0.119)”.
Zhu et al. [32]	2013	14,885,014+	29	Meta-analysis of cohort studies	“The positive association was observed for both men (RR 1.54, 95% CI: 1.30–1.82) and women (RR 1.50, 95% CI: 1.05–2.14)”. “In analysis stratified by study design, the summary RR was 1.29 (95% CI 1.20–1.39) in cohort studies. However, diabetes was not associated with mortality from bladder cancer in cohort studies of diabetic patients (RR 1.19, 95% CI 0.58–2.43)”.

Xu et al., 2017 [31] and Zhu et al. [32] both include studies: Woolcotta et al., 2011, Tripathi et al., 2002, Inoue et al., 2006, Khan et al., 2006, Jee et al., 2005, Athcison et al., 2011, Marriane et al., 2009, Tseng et al., 2011, and Ogunleye et al., 2009.