Sample size determination for conducting a pilot study to assess reliability of a questionnaire.

This article is a narrative review that discusses the recommended sample size requirements to design a pilot study to assess the reliability of a questionnaire. A list of various sample size tables that are based on the kappa agreement test, intra-class correlation test and Cronbach's alpha test has been compiled together. For all calculations, type I error (alpha) was set at a maximum value of 0.05, and power was set at a minimum value of 80.0%. For the kappa agreement test, intra-class correlation test, and Cronbach's alpha test, the recommended minimum sample size requirement based on the ideal effect sizes shall be at least 15, 22, and 24 subjects respectively. By making allowances for a non-response rate of 20.0%, a minimum sample size of 30 respondents will be sufficient to assess the reliability of the questionnaire. The clear guideline of minimum sample size requirement for the pilot study to assess the reliability of a questionnaire is discussed and this will ease researchers in preparation for the pilot study. This study provides justification for a minimum requirement of a sample size of 30 respondents specifically to test the reliability of a questionnaire.

Prevalence of true resistant hypertension in those referred for uncontrolled hypertension in Malaysia: A comparison using different definitions.

Resistant hypertension is a well-recognised clinical challenge. However, the definition and epidemiology of true resistant hypertension (RH) are less understood, especially in Asia. This cross-sectional study examined the prevalence of RH referred from primary care clinics based on various guidelines. RH was defined as blood pressure (BP) being above the threshold using ambulatory blood pressure monitoring despite adequate lifestyle measures and optimal treatment with ≥3 medications at maximally tolerated doses. Between one in four (n = 94, 24.0% using Malaysian guidelines) and up to two-thirds (n = 249, 63.7% using 2018 American guidelines) of adults referred for uncontrolled hypertension met the criteria of true RH. Of those with RH, a further one-quarter (n = 26, 26.6%) were deemed to have refractory hypertension (elevated BP despite treatment with at least 5 antihypertensive medications). Adults with RH were generally younger, more likely to be male, had a higher BMI and were more likely to have gout, CKD, and angina compared to those with controlled hypertension. The prevalence of RH amongst Asian adults with poor hypertension control is high. A concerted effort is needed to reduce the high burden of RH, especially among this population.

Smartphone electrocardiogram for detecting atrial fibrillation after a cerebral ischaemic event: a multicentre randomized controlled trial.

AIMS: Atrial fibrillation (AF) is a preventable cause of ischaemic stroke but it is often undiagnosed and undertreated. The utility of smartphone electrocardiogram (ECG) for the detection of AF after ischaemic stroke is unknown. The aim of this study is to determine the diagnostic yield of 30-day smartphone ECG recording compared with 24-h Holter monitoring for detecting AF ≥30 s. METHODS AND RESULTS: In this multicentre, open-label study, we randomly assigned 203 participants to undergo one additional 24-h Holter monitoring (control group, n = 98) vs. 30-day smartphone ECG monitoring (intervention group, n = 105) using KardiaMobile (AliveCor®, Mountain View, CA, USA). Major inclusion criteria included age ≥55 years old, without known AF, and ischaemic stroke or transient ischaemic attack (TIA) within the preceding 12 months. Baseline characteristics were similar between the two groups. The index event was ischaemic stroke in 88.5% in the intervention group and 88.8% in the control group (P = 0.852). AF lasting ≥30 s was detected in 10 of 105 patients in the intervention group and 2 of 98 patients in the control group (9.5% vs. 2.0%; absolute difference 7.5%; P = 0.024). The number needed to screen to detect one AF was 13. After the 30-day smartphone monitoring, there was a significantly higher proportion of patients on oral anticoagulation therapy at 3 months compared with baseline in the intervention group (9.5% vs. 0%, P = 0.002). CONCLUSIONS: Among patients ≥55 years of age with a recent cryptogenic stroke or TIA, 30-day smartphone ECG recording significantly improved the detection of AF when compared with the standard repeat 24-h Holter monitoring.

COVID-19 testing strategy in response to infection among healthcare workers in a large non-COVID-designated hospital.

Sarawak General Hospital, which is the only public access tertiary referral center in Sarawak State for all clinical specialties, was designated a hybrid hospital to treat both COVID-19 and non-COVID-19 patients. During the initial surge of patients admitted with COVID-19, there was also a corresponding increase in health-care workers (HCWs) detected with COVID-19 infection. The latter being isolated, and the large number of staff members that had come into contact with COVID-19 being quarantined from work, placed further strain on the health-care services. The staff mass screening strategy was a policy decision made by the hospital in response to infection among HCWs, and it aimed to reduce in-hospital transmission (particularly among asymptomatic staff), mitigate workforce depletion due to quarantining, and protect the health-care workforce. In this study, we assessed the detection rate of COVID-19 infection from staff mass testing over a five-week period, and described our experience of adopting this surveillance screening strategy alongside ongoing contact tracing and symptomatic screening strategies. Although it was thought that such periodic staff surveillance might be helpful in protecting the health-care workforce within a short period, the long-term implications, especially in settings with limited resources, is significant and therefore explored in this paper. Our findings might provide an evidence-based reference for the future planning of an optimal strategy with the least compromise in care for a larger proportion of non-COVID-19 patients amid efforts against COVID-19 in a large non-COVID-designated hospital with hybrid status.