. 2020 Feb 21;4(2):366–371. doi: 10.1016/j.jseint.2019.12.011

Table III.

Multiple negative binomial regression model for predictors of number of positive cultures

Model outcome and predictor variables^∗	Bootstrapped parameter estimates
Model outcome and predictor variables^∗	Mean estimate	SD	95% CI for mean estimate	GM	95% CI for GM
Number of positive cultures
Intercept	–0.9585	0.3852	–1.7492, –0.3629	0.3834	0.1739, 0.6956
Sex (male vs. female)	0.8912	0.4089	0.2239, 1.7248	2.4381	1.2509, 5.6114
History of ipsilateral shoulder infection (yes vs. no)	1.2515	0.3451	0.7339, 1.9871	3.4955	2.0832, 7.2943

SD, standard deviation; CI, confidence interval; GM, geometric mean (natural antilogarithm of the ln mean estimate).

The parameter estimates were based on 10,000 bootstrap samples of the negative binomial model. The mean and variance were estimated on the logarithmic scale. For the 95% CI that does not contain zero, the respective mean parameter estimate is statistically significant at alpha = 0.05. Observed sample, N = 83.

^∗

Predictor variables for the model were selected from a pool of 10 potential predictor variables via SAS's PROC HPREDUCE to perform supervised variable selection and then implemented in the context of a negative binomial model that was based on 10,000 bootstrap samples.