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Table 4 Comparison of log-binomial and Robust Poisson methods for analysis of no pain associated with covariates*

From: A comparison of two methods for estimating prevalence ratios

Independent Variable

Level

Log Prevalence Ratio Estimate† (SE)

P-Value

  

Log-Binomial

Robust Poisson

Log-Binomial

Robust Poisson

Analgesic

A

B

1.0228 (0.3951)

1.0979 (0.3898)

1.0628 (0.3902)

1.1515 (0.3882)

0.0002

0.0123

Gender

Female

0.2259 (0.0726)

0.4584 (0.1808)

0.0416

0.0112

Age

 

-0.0376 (0.0119)

-0.0635 (0.0183)

0.0075

0.0005

  1. * Wald tests were used for the Robust Poisson method, and likelihood ratio tests were used for the log-binomial method. The latter were obtained by fitting a model without the effect being tested. The log-binomial method failed to converge for the 2 models containing both analgesic and age, and the COPY method approximation was used.
  2. † The intercept estimate was 1.1200 for the log-binomial method and 2.7438 for the Robust Poisson method. Of the 60 probability estimates, 9 were greater than unity for the Robust Poisson method, and the largest was 1.30.