A recent study published in BMC Medical Research Methodology investigated recruitment and retention strategies for healthcare workers participating in a longitudinal COVID-19 study across Scotland. The research highlights the challenges and successes of maintaining engagement in long-term studies involving healthcare professionals.
Recruitment Strategies and Site Variability
The study, which spanned ten sites, revealed diverse recruitment approaches ranging from electronic communications to face-to-face interactions. While some sites relied solely on electronic methods, others incorporated social media and word-of-mouth strategies. Interestingly, sites with more limited recruitment strategies sometimes exceeded their targets, suggesting that the effectiveness of a strategy is highly context-dependent. For example, Site B, which relied on electronic communication only, exceeded its recruitment target, while Site D, which combined electronic recruitment with word-of-mouth, did not meet its target.
The recruitment period varied significantly, from 13 to 160 days. Several sites (A, D, and J) experienced recruitment rates below 50% of their targets. Site A had a very short recruitment period and no face-to-face recruitment, Site D also lacked face-to-face recruitment, and Site J had a large target sample size.
Factors Influencing Withdrawal and Retention
Regular communication, feedback on study results, flexible appointments, and reminders were identified as key engagement strategies. Withdrawal rates within the first 12 months ranged from 3.1% to 24.8% across sites. The sites with the highest withdrawal rates included the largest (Sites J and K) and smallest (Site A) sites. Conversely, Site C, which focused on building relationships with participants through a dedicated research center and a strong research identity, demonstrated low withdrawal and high opt-in rates.
Analysis of 1,721 responses from participants who withdrew indicated that 'workload and work commitments' were the primary reasons for leaving the study (46.7%). Other significant factors included leaving employment (15.9%), medical reasons (11.6%), and logistical issues with attending appointments (5.6%). Only a small percentage of withdrawals (8.9%) were directly related to the study protocol or processes.
Demographic and Occupational Influences
Logistic regression analysis revealed that younger participants (18-24 years) had higher withdrawal rates, with nearly one-third withdrawing in the first year. Administrative staff also showed a higher propensity to withdraw compared to clinical staff, with an adjusted odds ratio of 1.57 (95% CI 1.21–2.03). Participants with direct patient contact were also more likely to withdraw, with an adjusted odds ratio of 1.35 (1.00–1.81).
Among participants remaining after one year, only 51.0% actively opted into the study extension. Younger individuals and participants from minority ethnic groups showed lower opt-in rates, with odds ratios of 0.52 (95% CI 0.38–0.70) compared to white participants. Administrative staff, however, had relatively high opt-in rates, with an odds ratio of 1.41 (95% CI 1.10–1.80).
Implications for Longitudinal Studies
The findings underscore the importance of tailored recruitment and retention strategies in longitudinal studies involving healthcare workers. Addressing workload concerns, providing flexible scheduling, and fostering a sense of community can significantly improve participant engagement and reduce attrition. Targeted interventions may be necessary to improve retention among younger and minority ethnic groups.
