Comments on 'Psychological intervention targeting distress for cancer patients: a meta analytic study investigating uptake and adherence' by Brebach and colleagues (2016)
Brebach et al. analyzed 53 studies reporting uptake and/or adherence rates of individual psychological interventions targeting distress in 12 323 cancer patients. Uptake rate was 60.1% and adherence rate 90.4% Moreover, factors predicting higher uptake and adherence were identified, including delivery of intervention close to diagnosis, by telephone and led by a nurse. This paper provides intervention researchers/clinicians with valuable information because uptake and adherence are important indicators of whether interventions are deemed effective in clinical practice. However, we raise two major concerns that should be taken into account when interpreting these results. First, the authors did not report how patients were recruited to the included interventions. In consecutive sampling all potentially eligible patients are assessed for eligibility, reflecting a more realistic estimate of uptake in routine clinical practice. For example, in the recruitment of a trial examining Problem Solving Therapy 970 cancer patients were screened for distress to establish eligibility; however, only 10% of the 366 distressed patients participated [1] By contrast, in convenience sampling (e.g. self referral recruitment) uptake rates are often much higher. Patients who refer themselves might also be more intrinsically motivated to participate than patients invited by their clinician or a researcher, consequently also increasing adherence. We believe that the reported uptake rate of 60.1% overestimates intervention uptake in consecutive samples, and it would have been of value to readers for Brebach et al. to explore the relationship between recruitment method and uptake/adherence in their review. Second, the authors do not report patients' type of cancer or disease stage. A poor performance status and poor prognosis can highly impact recruitment and adherence rates of psychological interventions. It might even explain why fewer psychological intervention studies target patient groups with a poor prognosis, such as lung cancer, compared with other cancer types, such as breast cancer. We commend the authors for their review quantifying adherence and uptake of psychological interventions targeting distress. However, by failing to discuss recruitment methods and clinical characteristics, we believe the authors provide an overestimated picture of uptake and adherence. More research is needed on how above mentioned factors are related to uptake and adherence, in order to help researchers and clinicians design feasible studies and deliver more accessible and clinically relevant interventions.
Psycho oncology