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Sample size calculation for prevalence of sleep disturbance in competitive senior level judo athletes in Canada
Document version
| Version | Alterations |
|---|---|
| 01 | Initial version |
Calculate the minimum sample size to be able to detect the prevalence of sleep disturbance as measured by the Pittsburgh Sleep Quality Index in competitive senior level judo athletes in Canada.
It is hypothesized that the prevalence of sleep disorders is high in competitive senior level judo athletes in Canada leading to psychological distress, on the order of 20%.
No data analysis is planned at this stage.
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This is a single-arm cross-sectional study.
Competitive senior level judo athletes aged 18+ years old will be included.
As this is a single-arm study, no exposures were defined for the prevalence calculation.
Specification of outcome measures (Zarin, 2011):
Primary outcome
Proportion of study participants with PSQI > 5.
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No data analysis is planned at this stage.
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All analyses will be performed using the significance level of 5%. All significance hypothesis tests and confidence intervals computed will be two-tailed.
The sample size calculation was done using the method described in Humphry (2004), which adjusts for imperfect diagnostic sensitivity and specificity. The parameters used in the calculation are shown in Table 1. The target population accounted for 3839 senior competitive judo athletes in November, 2022. Considering the hypothesized 20% true population prevalence the tolerance of 50% around this hypothesized value which would give a 95% CI of 10% to 30%.
Table: Table 1 Parameters for sample size calculation.
| Parameter | Value |
|---|---|
| Target population size (chosen) | 3839 |
| True population prevalence (assumed) | 20% |
| Tolerance (chosen) | 50% |
| Diagnostic sensitivity (chosen) | 89.6% |
| Diagnostic specificity (chosen) | 86.5% |
Assuming a sensitivity of 89.6% and a specificity of 86.5%, the sample size calculated of 136 is sufficient to detect a prevalence of 20% in the target population, within the specified tolerance.
This analysis was performed using statistical software R version 4.2.1.
The methods for the sample size calculated were implemented in the epiR package version 2.0.53.
Recommended reporting guideline
The adoption of the EQUATOR network (http://www.equator-network.org/) reporting guidelines have seen increasing adoption by scientific journals. All observational studies are recommended to be reported following the STROBE guideline (von Elm et al, 2014).
This document was elaborated following recommendations on the structure for Statistical Analysis Plans (Gamble, 2017) for better transparency and clarity.
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