NEWS

Objectives: There are limitations to defining multimorbidity (MM) based on a simple count of diseases. To address these limitations, the concept of complex MM (CMM) focuses on how many body systems are affected in a single patient, rather than counting comorbid conditions. This study compared the prediction of mortality among older Japanese adults between CMM and conventional MM.

Design: A population-based prospective cohort study.

Setting: The Japan Gerontological Evaluation Study, a nationwide longitudinal cohort study, which ran from 2010 to 2016.

Participants: Functionally independent individuals who were older than 65 and had complete illness data at the time of baseline survey were eligible.

Outcomes measure: CMM was defined as the coexistence of 3 or more body system disorders at baseline. We calculated the propensity for each individual to develop CMM based on a wide array of characteristics, including socioeconomic status and health behaviours. Individuals with and without CMM were then matched on their propensity scores before we estimated overall survival using a log-rank test.

Results: Our 6-year follow-up included 38 889 older adults: 20 233 (52.0%) and 7565 (19.5%) adults with MM and CMM, respectively. In the MM-matched cohort (n=15 666 pairs), the presence of MM was significantly associated with increased mortality (HR 1.07; 95% CI 1.01 to 1.14; p=0.02 by the log-rank test). A similar mortality association was found in the CMM-matched cohort (n=7524 pairs, HR, 1.07; 95% CI 0.99 to 1.16; p=0.08 by the log-rank test).

Conclusion: This is the first study to report the association between CMM and mortality among older adults in Japan. MM and CMM predict mortality in older adults to a similar degree. This finding needs to be replicated with more precision in larger samples.

Purpose: Gamification, the use of game design elements in nongame contexts, in combination with insights from behavioral economics has been applied increasingly to behavior change interventions. However, little is known about the effectiveness or scalability of this approach, especially in the long term. We tested a large-scale smartphone-based intervention to encourage physical activity among Japanese baseball fans using gamification techniques that leveraged fandom and inter-team competition inherent in sports.

Methods: A quasi-experimental study was conducted among fans of the Japanese Pacific League. The app, Pa-League Walk, included gamification elements, such as competition between opposing teams’ fans based on total daily step counts on game days (>60,000 free downloads since March 2016). We analyzed daily steps of 20,052 app users, supplemented by online survey data of 274 users and 613 matched controls. Difference-in-differences estimators evaluated change in daily steps before and after app installation in users versus matched controls.

Results: Users’ daily steps increased by 574 (95% confidence interval: 83, 1064) steps three months after installation, compared to controls. The increase was maintained for up to nine months (559 [99, 1018] more steps per day versus baseline), attenuating over a longer follow-up. Positive effect modification was found by high frequency of the app use (P < 0.001) but not by other covariables (P ≥ 0.14) such as education or income. Days with 10,000 steps achievement increased from 24.4% to 27.5% after the additional introduction of incentives (digital player photos) (P < 0.001).

Conclusion: Using existing fandom and solidarity, the gamification app increased physical activity at scale among baseball fans, including people with lower socioeconomic status under-represented in traditional health programs.