Fitbit-Based Interventions for Healthy Lifestyle Outcomes: Systematic Review and Meta-Analysis

Background Unhealthy behaviors, such as physical inactivity, sedentary lifestyle, and unhealthful eating, remain highly prevalent, posing formidable challenges in efforts to improve cardiovascular health. While traditional interventions to promote healthy lifestyles are both costly and effective, wearable trackers, especially Fitbit devices, can provide a low-cost alternative that may effectively help large numbers of individuals become more physically fit and thereby maintain a good health status. Objective The objectives of this meta-analysis are (1) to assess the effectiveness of interventions that incorporate a Fitbit device for healthy lifestyle outcomes (eg, steps, moderate-to-vigorous physical activity, and weight) and (2) to identify which additional intervention components or study characteristics are the most effective at improving healthy lifestyle outcomes. Methods A systematic review was conducted, searching the following databases from 2007 to 2019: MEDLINE, EMBASE, CINAHL, and CENTRAL (Cochrane). Studies were included if (1) they were randomized controlled trials, (2) the intervention involved the use of a Fitbit device, and (3) the reported outcomes were related to healthy lifestyles. The main outcome measures were related to physical activity, sedentary behavior, and weight. All the studies were assessed for risk of bias using Cochrane criteria. A random-effects meta-analysis was conducted to estimate the treatment effect of interventions that included a Fitbit device compared with a control group. We also conducted subgroup analysis and fuzzy-set qualitative comparative analysis (fsQCA) to further disentangle the effects of intervention components. Results Our final sample comprised 41 articles reporting the results of 37 studies. For Fitbit-based interventions, we found a statistically significant increase in daily step count (mean difference [MD] 950.54, 95% CI 475.89-1425.18; P<.001) and moderate-to-vigorous physical activity (MD 6.16, 95% CI 2.80-9.51; P<.001), a significant decrease in weight (MD −1.48, 95% CI −2.81 to −0.14; P=.03), and a nonsignificant decrease in objectively assessed and self-reported sedentary behavior (MD −10.62, 95% CI −35.50 to 14.27; P=.40 and standardized MD −0.11, 95% CI −0.48 to 0.26; P=.56, respectively). In general, the included studies were at low risk for bias, except for performance bias. Subgroup analysis and fsQCA demonstrated that, in addition to the effects of the Fitbit devices, setting activity goals was the most important intervention component. Conclusions The use of Fitbit devices in interventions has the potential to promote healthy lifestyles in terms of physical activity and weight. Fitbit devices may be useful to health professionals for patient monitoring and support. Trial Registration PROSPERO International Prospective Register of Systematic Reviews CRD42019145450; https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42019145450

High risk Due to the nature of the intervention and control conditions make blinding impossible.

Blinding of outcome assessment (detection bias)
Low risk Outcome measures were obtained by assessors blinded to treatment assignment.(p.187)

Incomplete outcome data (attrition bias)
Low risk Sensitivity analyses were conducted on all outcomes using baseline observation carried forward imputation and linear mixed-effect regression modeling [24].(p.189) Selective reporting (reporting bias)

Low risk
The study protocol is not available but it is clear that the published reports include all expected outcomes, including those that were pre-specified.

Other bias Low risk
The study appears to be free of other sources of bias.High risk Due to the nature of the intervention and control conditions make blinding impossible.

Blinding of outcome assessment (detection bias)
Low risk Blinding of outcomes assessment was not mentioned but the outcome measurement is not likely to be influenced by lack of blinding because outcomes were objectively measured.

Low risk
No reason for missing data were provided.Missing data for outcome were balanced accross both groups and missing data were not big enough to have a clinically impact on the observed effect size.

Low risk
The study protocol is available and all of the study s pre-specified (primary and secondary) outcomes that are of interest in the review have been reported in the pre-specified way.

Other bias Low risk
The study appears to be free of other sources of bias.Low risk Blinding of outcomes assessment was not mentioned but the outcome measurement is not likely to be influenced by lack of blinding because outcomes were objectively measured.

Incomplete outcome data (attrition bias)
High risk "During the course of the intervention, 27 intervention subjects had at least one problem related to the activity monitor.There were 4 occasions when subjects lost their activity monitors, 18 occasions where the wristband or clip was lost or damaged, 6 when the charger was lost, and 26 where the activity monitor required a factory settings or password reset.Although all lost or damaged items were replaced, these mishaps resulted in disruption to the study and periods where the activity monitor was not worn" (p.9) Selective reporting (reporting bias)

Low risk
The study protocol is available and all of the study s pre-specified (primary and secondary) outcomes that are of interest in the review have been reported in the pre-specified way.

Other bias Low risk
The study appears to be free of other sources of bias.

Low risk
The study protocol is available and all of the study s pre-specified (primary and secondary) outcomes that are of interest in the review have been reported in the pre-specified way.

Other bias Low risk
The study appears to be free of other sources of bias.
DiFrancisco-Donoghue, 2018 Blinding of participants and personnel (performance bias) High risk Due to the nature of the intervention and control conditions make blinding impossible.

Blinding of outcome assessment (detection bias)
Low risk Blinding of outcomes assessment was not mentioned but the outcome measurement is not likely to be influenced by lack of blinding because outcomes were objectively measured.

Incomplete outcome data (attrition bias)
Low risk Missing outcome data balanced in numbers across intervention groups, with similar reasons for missing data.

Low risk
The study protocol is available and all of the study s pre-specified (primary and secondary) outcomes that are of interest in the review have been reported in the pre-specified way.
Other bias High risk Significant differences between groups at baseline.Blinding of participants and personnel (performance bias)

Duscha, 2018
High risk Due to the nature of the intervention and control conditions make blinding impossible.

Blinding of outcome assessment (detection bias)
Low risk Blinding of outcomes assessment was not mentioned but the outcome measurement is not likely to be influenced by lack of blinding because outcomes were objectively measured.

Incomplete outcome data (attrition bias)
Low risk Missing outcome data balanced in numbers across intervention groups, with similar reasons for missing data across groups (p.106) Selective reporting (reporting bias)

Low risk
The study protocol is available and all of the study s pre-specified (primary and secondary) outcomes that are of interest in the review have been reported in the pre-specified way.
Other bias High risk Two authors were working for Vida Health, the firm producing the Health coaching

Risk of bias table
Bias Authors' judgement Support for judgement

Random sequence generation (selection bias)
Unclear risk Insufficient information about the sequence generation process to permit judgement of Yes or No .

Allocation concealment (selection bias)
Unclear risk Insufficient information to permit judgement of Yes or No .

Blinding of participants and personnel (performance bias)
High risk Due to the nature of the intervention and control conditions make blinding impossible.

Blinding of outcome assessment (detection bias)
Low risk Blinding of outcomes assessment was not mentioned but the outcome measurement is not likely to be influenced by lack of blinding because outcomes were objectively measured.
Test 25-Jun-2020 Review Manager 5.3 9 Incomplete outcome data (attrition bias) Low risk Attrition is balanced across groups and not enough to induce clinically relevant bias in observed effect sizes.

Low risk
The study protocol is not available but it is clear that the published reports include all expected outcomes.

Other bias Low risk
The study appears to be free of other sources of bias.

Low risk
The study protocol is not available but it is clear that the published reports include all expected outcomes, including those that were pre-specified.

Other bias Low risk
The study appears to be free of other sources of bias.

Low risk
The study protocol is available and all of the study s pre-specified primary outcomes have been reported in the pre-specified way.

Other bias Low risk
The study appears to be free of other sources of bias.Blinding of participants and personnel (performance bias)

Gilmore, 2017
High risk Due to the nature of the intervention and control conditions make blinding impossible.

Blinding of outcome assessment (detection bias)
Low risk Blinding of outcomes assessment was not mentioned but the outcome measurement is not likely to be influenced by lack of blinding because outcomes were objectively measured.

Incomplete outcome data (attrition bias)
Low risk Attrition was not enough to have a clinically relevant impact on the intervention effect estimate.

Low risk
The study protocol is available and all of the study s pre-specified (primary and secondary) outcomes that are of interest in the review have been reported in the pre-specified way.

Other bias Low risk
The study appears to be free of other sources of bias.

Incomplete outcome data (attrition bias)
High risk High imbalance between "App-plus" and the other two groups in lost to follow-up.Plausible effect size among missing outcomes enough to induce clinically relevant bias in observed effect size.

Low risk
The study protocol is available and all of the study s pre-specified (primary and secondary) outcomes that are of interest in the review have been reported in the pre-specified way

Other bias Low risk
The study appears to be free of other sources of bias.
Hartman, 2016 High risk Due to the nature of the intervention and control conditions make blinding impossible.

Blinding of outcome assessment (detection bias)
Low risk Blinding of outcomes assessment was not mentioned but the outcome measurement is not likely to be influenced by lack of blinding because outcomes were objectively measured.

Incomplete outcome data (attrition bias)
Low risk Missing data were assumed missing at random and were accounted for in the longitudinal random effects models by using a likelihood-based estimation method, which uses all available data and does not ignore subjects with missing data.
In analysis models that used only a single time point, a complete cases analysis was carried out, with those missing data dropped from the analysis.

Low risk
The study protocol is not available but it is clear that the published reports include all expected outcomes, including those that were pre-specified.

Other bias Low risk
The study appears to be free of other sources of bias.High risk Due to the nature of the intervention and control conditions make blinding impossible.

Blinding of outcome assessment (detection bias)
Low risk Blinding of outcomes assessment was not mentioned but the outcome measurement is not likely to be influenced by lack of blinding because outcomes were objectively measured.

Incomplete outcome data (attrition bias)
Low risk All analyses were performed using an intent-to-treat principal, with missing data assumed missing at random and accounted for in the longitudinal random-effects models by using a likelihood-based estimation method, which uses all available data and does not omit individuals with partially missing data.(p.194) Selective reporting (reporting bias)

Low risk
The study protocol is available and all of the study s pre-specified outcomes that are of interest in the review have been reported in the pre-specified way.

Other bias Low risk
The study appears to be free of other sources of bias.Unclear risk Insufficient information about the sequence generation process to permit judgement of Low risk or High risk .

Allocation concealment (selection bias)
Unclear risk Insufficient information to permit judgement of Low risk or High risk .
Blinding of participants and personnel (performance bias) High risk Due to the nature of the intervention and control conditions make blinding impossible.

Blinding of outcome assessment (detection bias)
Low risk Blinding of outcomes assessment was not mentioned but the outcome measurement is not likely to be influenced by lack of blinding because the primary outcome was objectively measured.

Incomplete outcome data (attrition bias)
Low risk Plausible effect size (difference in means or standardized difference in means) among missing outcomes not enough to have a clinically relevant impact on observed effect size.

Low risk
The study protocol is not available but it is clear that the published reports include all expected outcomes, including those that were pre-specified

Other bias Low risk
The study appears to be free of other sources of bias.
Jennings, 2016 Blinding of participants and personnel (performance bias) High risk Due to the nature of the and control conditions make blinding impossible.

Blinding of outcome assessment (detection bias)
Low risk Blinding of outcomes assessment was not mentioned but the outcome measurement is not likely to be influenced by lack of blinding because outcomes were objectively measured.

Incomplete outcome data (attrition bias)
Unclear risk Insufficient reporting of attrition/exclusions to permit judgement of Yes or No .

Low risk
The study protocol is not available but it is clear that the published reports include all expected outcomes, including those that were pre-specified

Other bias Low risk
The study appears to be free of other sources of bias.

Low risk
The study protocol is available and all of the study s pre-specified (primary and secondary) outcomes that are of interest in the review have been reported in the pre-specified way.

Other bias Low risk
The study appears to be free of other sources of bias.Blinding of participants and personnel (performance bias)

Kooiman, 2018
High risk Due to the nature of the intervention and control conditions make blinding impossible.

Blinding of outcome assessment (detection bias)
Low risk Blinding of outcomes assessment was not mentioned but the outcome measurement is not likely to be influenced by lack of blinding because primary outcomes were objectively measured.

Incomplete outcome data (attrition bias)
Low risk Within the intervention group, a mixed models analysis was used to analyze the change of physical activity over time, measured as average steps per day from week 0 (baseline) until week 12.The advantage of mixed models is that this method can handle missing data; for example, a participant with a missing week of average steps per day data would still be included in the analysis.(p.344).

Low risk
The study protocol is available and all of the study s pre-specified (primary and secondary) outcomes that are of interest in the review have been reported in the pre-specified way.

Other bias Low risk
The study appears to be free of other sources of bias.
Li, 2017 High risk Due to the nature of the intervention and control conditions make blinding impossible.

Blinding of outcome assessment (detection bias)
Low risk Blinding of outcomes assessment was not mentioned but the outcome measurement is not likely to be influenced by lack of blinding because primary outcomes were objectively measured.

Low risk
We assessed the impact of missing data on the estimated effects of group assignment using imputation methods as described in van Buuren [45].Specifically, we generated 10 imputed values using alternative random variates derived in a linear regression model, which included group, sex, baseline age, and baseline body mass index as predictors.We repeated the analyses using the 10 imputed values, and compared the conclusions and estimates against the main analysis, which assumed that data were missing at random.(p. 5) Selective reporting (reporting bias)

Low risk
The study protocol is available and all of the study s pre-specified (primary and secondary) outcomes that are of interest in the review have been reported in the pre-specified way.

Other bias Low risk
The study appears to be free of other sources of bias.High risk Due to the nature of the intervention and control conditions make blinding impossible.

Blinding of outcome assessment (detection bias)
Low risk An intention-to-treat analysis was performed by a biostatistician who was blinded to the group assignment.(p.4).

Low risk
Plausible effect size (difference in means or standardized difference in means) among missing outcomes not enough to have a clinically relevant impact on observed effect size.

Low risk
The study protocol is available and all of the study s pre-specified (primary and secondary) outcomes that are of interest in the review have been reported in the pre-specified way.

Other bias Low risk
The study appears to be free of other sources of bias.
Lystrup, 2016 Unclear risk Insufficient information about the sequence generation process to permit judgement of Yes or No .