Both sets of results were obtained following missing data imputation (note that web table 1 shows unadjusted results using the complete case samples).
In order to assess the impact of missing data on our findings, we examined the results when performing the analyses using mean imputation method, and when using the complete case analysis.
When the analyses were run separately for males and females using the complete case set, we found that for males (n = 57), baseline TUG was not associated with baseline EQ-5D HSUVs (B = -0.10, p = .671) nor change in EQ-5D HSUVs over time (p = 0.139).
While the size of the cohort is a key strength of this study, there has been considerable dropout since the study's conception, and this impacts on analyses both when using the complete case and the partially observed data sets of alcohol measures.
Analysis models on the imputed data sets included the same variables as those used in the analysis models using the complete case analysis approach, that is, age, deprivation, tumour type and screening detection status for breast cancer, and age, sex, deprivation and tumour type for lung cancer, including a random effect for Primary Care Trust.
For sensitivity analysis, the new dataset (n = 115) was derived from original data set by using the complete case analysis in which only questionnaires without DK responses were retained for the analysis, and scores were calculated by summing the response codes to the questionnaire items.
These imputed data have been used in all analysis, with a sensitivity analysis using the complete cases.
In this case the models (1) and (2) can be fitted as two separate conventional logistic regressions, where model (1) is fitted using the complete cases.
Supplementary analysis was performed to check the possible influence of partially missing data in the crude and Model I analyses, using the complete cases of Model II.
The crude and adjusted odds ratio with 95% confidence intervals is given for 14 high-risk HPV types, pooled and type-specific, using the complete cases (left figure) and the imputed data (right figure).
For the initial analysis we used the complete case method to deal with missing data.
