Lee mortality index as comorbidity measure in patients undergoing radical cystectomy

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Table 3 Optimal Cox proportional hazard models predicting overall (upper part) and competing mortality (lower part) after radical cystectomy

Endpoint overall mortality
Category	Hazard ratio	95% confidence interval	p
Lee mortality index (continuous variable, per unit increase)	1.06	1.00-1.12	0.0415
Age-adjusted Charlson score (continuous variable, per unit increase)	1.08	1.02-1.15	0.0100
Locally advanced, lymph node-negative disease	2.23	1.72-2.89	<0.0001
Lymph node-positive disease	5.41	4.09-7.15	<0.0001
10-20 lymph nodes removed	0.82	0.63-1.08	0.1614
>20 lymph nodes removed	0.72	0.52-0.98	0.0340
ASA 2	9.66	1.35-69.27	0.0274
ASA 3-4	14.35	2.00-103.76	0.0083
Adjuvant cisplatin-based chemotherapy	0.53	0.40-0.70	<0.0001
Endpoint competing mortality
Category	Hazard ratio	95% confidence interval	P
Lee mortality index (continuous variable, per unit increase)	1.27	1.19-1.35	<0.0001
ASA 3-4	1.62	1.62-2.26	0.0044
Locally advanced, lymph node-negative disease	1.31	0.92-1.87	0.1313
Lymph node-positive disease	0.54	0.35-0.85	0.0071

In the analysis of competing mortality, the ASA classes 1 and 2 were combined since in the 15 patients with ASA class 1 no competing death occurred up to now prohibiting the use of this category as reference. Combining the ASA classes 1 and 2 did not change the optimal model predicting overall mortality meaningfully (hazard ratio for ASA 3–4 versus 1–2: 1.53, p = 0.0002). The inverse relationship between lymph node involvement and competing mortality may be explained by the clear overweight of bladder cancer mortality in this subgroup. Reference categories: organ confined, lymph node-negative disease, <10 lymph nodes removed, ASA 1 or ASA 1–2, respectively, no adjuvant cisplatin-based chemotherapy or unknown (n = 10).