Meta-analyses have shown that digital mental health apps can be efficacious in reducing symptoms of depression and anxiety. However, real-world usage of apps is typically not sustained over time, and no studies systematically examine which features increase sustained engagement with apps or the relationship between engagement features and clinical efficacy. We conducted a systematic search of the literature to identify empirical studies that (1) investigate standalone apps for depression and/or anxiety in symptomatic participants and (2) report at least one measure of engagement. Features intended to increase engagement were categorized using the persuasive system design (PSD) framework and principles of behavioral economics. Twenty-five studies with 4159 participants were included in the analysis. PSD features were commonly used, whereas behavioral economics techniques were not. Smartphone apps were efficacious in treating symptoms of anxiety and depression in randomized controlled trials, with overall small-to-medium effects (g = 0.2888, SE = 0.0999, z(15) = 2.89, p = 0.0119, Q(df = 14) = 41.93, p < 0.0001, I2 = 66.6%), and apps that employed a greater number of engagement features as compared to the control condition had larger effect sizes (β = 0.0450, SE = 0.0164, t(15) = 2.7344, p = 0.0161). We observed an unexpected negative association between PSD features and engagement, as measured by completion rate (β = −0.0293, SE = 0.0121, t(17) = 02.4142, p = 0.0281). Overall, PSD features show promise for augmenting app efficacy, though engagement, as reflected in study completion, may not be the primary factor driving this association. The results suggest that expanding the use of PSD features in mental health apps may increase clinical benefits and that other techniques, such as those informed by behavioral economics, are employed infrequently.

Summary Background The phase 3 (UNIFI) trial of ustekinumab (anti‐interleukin 12/23) demonstrated efficacy even after prior biologic failure in adult ulcerative colitis (UC), but paediatric data are lacking. Aim To prospectively monitor efficacy and serum concentrations of ustekinumab given to children with UC refractory to other biologics. Methods Children with anti‐TNF refractory UC initiating ustekinumab intravenously at sites of the Canadian Children IBD Network prior to 12/2019 are included. The primary endpoint was steroid‐free clinical remission with subcutaneous ustekinumab at 52 weeks (Paediatric Ulcerative Colitis Activity Index <10, no steroids ≥4 weeks). Ustekinumab levels were measured after week 20. Endoscopic improvement was defined as Mayo endoscopic subscore ≤1, or faecal calprotectin (FCP) <250 μg/g if not re‐colonoscoped. Results At six sites between 01/2018 and 11/2019, 25 children (median [IQR] age 14.8 years [12.3‐16.2], 72% female) with UC duration 2.3 years (1.1‐4.2) received intravenous ustekinumab (median dose/kg of 6.4 [5.5‐7.5] mg). All patients had failed prior infliximab therapy, and 12 (48%) also vedolizumab. Five patients discontinued ustekinumab after IV induction (four undergoing colectomy). On intent to treat basis, 44% achieved the primary endpoint of steroid‐free remission at week 52, including nine (69%) of 13 who previously treated with anti‐TNF only vs two (17%) of 12 who previously failed also by vedolizumab (P = 0.008). Seven of 11 remitters met the criteria for endoscopic improvement. The median (IQR) trough levels (μg/mL) were greater with q4 vs q8 weekly dosing (8.7 [4.6‐9.9] vs 3.8 [12.7‐4.8]) P = 0.02, but greater exposure was not associated with a superior rate of clinical remission. No adverse events were associated with therapy. Conclusion Ustekinumab demonstrated efficacy in this paediatric cohort with otherwise treatment‐refractory UC. Treatment failure was not due to inadequate drug exposure.

IntroductionEarly diagnosis of prediabetes based on blood sampling for the oral glucose tolerance test (OGTT) is crucial for intervention but multiple barriers hinder its uptake. This study aimed to assess the feasibility and precision of a self-administered capillary OGTT for type-2 diabetes mellitus (T2DM) in high-risk individuals.Research design and methodsParticipants with history of gestational diabetes or prediabetes were recruited in primary care. Due to their prediabetic status and previous diagnosis of gestational diabetes mellitus, a proportion of participants had previous experience doing OGTT. They self-administered the capillary OGTT and concurrently their venous glucose samples were obtained. They filled a questionnaire to collect their demographic information, views of their capillary OGTT, and their preferred site of the test.ResultsAmong 30 participants enrolled in this feasibility study, 93.3% of them felt confident of performing the capillary OGTT themselves, and 70.0% preferred the test at home. Older, less educated participants found it less acceptable. Mean capillary glucose values were significantly higher than venous glucose values, with mean difference at 0.31 mmol/L (95% CI 0.13 to 0.49) at fasting, and 0.47 mmol/L (95% CI 0.12 to 0.92) 2 hours post-OGTT. Capillary and venous glucose measurements were correlated for fasting (r=0.95; p<0.001) and 2-hour-post-OGTT (r=0.95;p<0.001). The Fleiss-Kappa Score (0.79, p<0.0001) indicated fair agreement between the two methods. The capillary OGTT had excellent sensitivity (94.1%) and negative predictive value (NPV=91.7%) in identifying prediabetes or T2DM status, vis-a-vis to venous glucose samples.ConclusionSelf-administered capillary OGTT is feasible and acceptable, especially among younger adults, with excellent sensitivity and NPV compared with plasma-based OGTT.