The study did not employ a run-in period to exclude those who would heal under standard care alone.
The success of downstaging, therefore, is partly a result of the ability of the followup period to exclude patients with aggressive and poorly responsive tumors.
The use of antibiotics was also compared between the two units over the time period to exclude this as a confounding variable.
We repeated analyses after excluding the 31 employees who died in the three years immediately after the three year sickness absence exposure period, to exclude the possibility that absence close to death might account for our findings.
After randomising one woman in the early stages of the study period who had had acupuncture within the past week before randomisation, we decided for the remainder of the study period to exclude all women who had recently received similar treatment.
In our study, 5-ARI was used because of lower urinary tract symptoms, most likely caused by benign prostatic hyperplasia, and we had little means other than introducing a restriction period to exclude prevalent cancers.
Many such analyses require that the investigator define a prevalence period to exclude patients with pre-existing conditions from the incidence risk set [ 2, 3, 6, 8, 11, 12, 15].
Histological diagnosis of MPM was confirmed using immunohistochemistry. Diagnosis of BAPE was based on a nonmalignant pleural biopsy, a history of asbestos exposure, and the exclusion of the other causes, together with a three-year observation period to exclude malignancy.
