Table 1

DESCRIPTIVE measures, variable- oriented hypotheses
Research question Outcome Method of analysis Results from the model data set
All respondents, n = 244 Highly compliant respondents, answering 80% (≥15/18 weeks), n = 161
1A: Crude outcome Total number of 1: days with pain from 18 weekly measures, 2: weeks reported Summaries. 1: Mean 33.0, Range 0 – 126 Short duration: Mean 24.5, Range 0-124 Long duration: 41.1, Range 0-126 2: Mean 15.2. Range 2-18 1: Mean 36.4. Range 0-126 Short duration: Mean 27.4, Range 0-124 Long duration: mean 45.4, Range 4-126 2: Mean 17.3, Range 15-18
1B: Difference in weekly outcome between groups Average number of pain days per week Student’s t-test Short duration: 1.6 Long duration: 2.8 p < 0.001 Short duration: 1.6 Long duration: 2.6 p < 0.001
2A: Proportion with different levels of the condition Incidence of recovered = reporting 0 pain days week by week Proportion, i.e. percentage of subjects who are recovered compared to those who are not Illustrated in Figure 1a Proportions recovered week 8: Short duration: 58.6% Long duration: 30.7% OR = 3.19 (1.88 – 5.72) RR = 1.8 (1.62 – 1.93) Long duration reference category Illustrated in Figure 1b Proportions recovered week 8: Short duration: 58.3% Long duration: 32.5% OR = 2.91 (1.50 – 5.65) RR = 1.66 (1.51 – 1.83) Long duration reference category
2B: Incidence at a prespecified time point Proportion of patients recovered = reporting 0 or 1 pain days at the chosen time, e.g. the 5th week Logistic regression (or other generalised linear regression models) Short duration: 58.7% Long duration: 27.7% OR = 3.71 (2.1-6.6) RR = 1.75 (1.4 – 2.3) Long duration reference category Short duration: 58.2% Long duration: 28.0% OR = 3.58 (1.8 - 7.0) RR = 1.72 (1.34 – 2.3) Long duration reference category

Axén et al.

Axén et al. BMC Medical Research Methodology 2012 12:105   doi:10.1186/1471-2288-12-105

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