Table 4.
Coefficients of multiple regression analysis for digital biomarkers and 9-item Patient Health Questionnaire (PHQ-9) scores. Fully adjusted models.
| Predictor | βa (95% CI) | P value | |||
| Model 1 | |||||
|
|
Digital biomarker: IS.st.wdb | –2.974 (–5.202 to –0.747) | .009 | ||
|
|
Age | –0.114 (–0.163 to –0.064) | <.001 | ||
|
|
Gender (male) | –0.165 (–0.811 to 0.481) | .62 | ||
|
|
Ethnic group (Indian) | –0.297 (–1.393 to 0.798) | .59 | ||
|
|
Ethnic group (Malay) | –0.036 (–1.629 to 1.556) | .96 | ||
|
|
Ethnic group (others) | 1.012 (–0.021 to 2.045) | .06 | ||
|
|
Marital status (single) | –0.633 (–1.341 to 0.076) | .08 | ||
|
|
Education level (university degree) | –1.023 (–2.079 to 0.034) | .06 | ||
|
|
Monthly income level (SGD 4000c and above) | 0.283 (–0.422 to 0.988) | .43 | ||
|
|
Alcohol consumption (yes) | –0.201 (–0.834 to 0.433) | .53 | ||
|
|
Smoking status (nonsmoker) | –0.768 (–2.075 to 0.54) | .25 | ||
|
|
Self-rated health (fair) | 1.528 (–0.103 to 3.159) | .07 | ||
|
|
Self-rated health (good) | 0.597 (–0.631 to 1.824) | .34 | ||
|
|
Self-rated health (very good) | –0.026 (–1.246 to 1.194) | .97 | ||
|
|
UCLA (University of California, Los Angeles) Loneliness Scale score | 0.094 (0.062 to 0.127) | <.001 | ||
|
|
Sleep Hygiene Index (SHI) score | 0.082 (0.022 to 0.143) | .008 | ||
|
|
Pittsburgh Sleep Quality Index (PSQI) score | 0.362 (0.227 to 0.496) | <.001 | ||
|
|
Epworth Sleepiness Scale (ESS) score | 0.06 (–0.014 to 0.134) | .11 | ||
|
|
Intercept | 3.407 (–0.167 to 6.98) | .06 | ||
| Model 2 | |||||
|
|
Digital biomarker: AC.st.15m.wdd | –3.843 (–7.567 to –0.119) | .04 | ||
|
|
Age | –0.113 (–0.163 to –0.063) | <.001 | ||
|
|
Gender (male) | –0.063 (–0.712 to 0.586) | .85 | ||
|
|
Ethnic group (Indian) | –0.19 (–1.285 to 0.904) | .73 | ||
|
|
Ethnic group (Malay) | –0.038 (–1.64 to 1.563) | .96 | ||
|
|
Ethnic group (others) | 1.126 (0.09 to 2.162) | .03 | ||
|
|
Marital status (single) | –0.635 (–1.348 to 0.077) | .08 | ||
|
|
Education level (university degree) | –1.056 (–2.12 to 0.007) | .051 | ||
|
|
Monthly income level (SGD 4000 and above) | 0.309 (–0.402 to 1.02) | .39 | ||
|
|
Alcohol consumption (yes) | –0.229 (–0.87 to 0.413) | .48 | ||
|
|
Smoking status (nonsmoker) | –0.741 (–2.056 to 0.573) | .27 | ||
|
|
Self-rated health (fair) | 1.574 (–0.066 to 3.213) | .06 | ||
|
|
Self-rated health (good) | 0.604 (–0.631 to 1.838) | .34 | ||
|
|
Self-rated health (very good) | –0.031 (–1.259 to 1.196) | .96 | ||
|
|
UCLA Loneliness Scale score | 0.092 (0.059 to 0.124) | <.001 | ||
|
|
SHI score | 0.091 (0.031 to 0.151) | .003 | ||
|
|
PSQI score | 0.351 (0.216 to 0.486) | <.001 | ||
|
|
ESS score | 0.062 (–0.013 to 0.136) | .11 | ||
|
|
Intercept | 2.526 (–0.921 to 5.973) | .15 | ||
| Model 3 | |||||
|
|
Digital biomarker: NHR.0406.cve | 9.096 (0.333 to 17.859) | .04 | ||
|
|
Age | –0.114 (–0.164 to –0.064) | <.001 | ||
|
|
Gender (male) | –0.246 (–0.909 to 0.416) | .47 | ||
|
|
Ethnic group (Indian) | –0.188 (–1.282 to 0.907) | .74 | ||
|
|
Ethnic group (Malay) | –0.193 (–1.802 to 1.415) | .81 | ||
|
|
Ethnic group (others) | 0.985 (–0.058 to 2.028) | .06 | ||
|
|
Marital status (single) | –0.661 (–1.373 to 0.051) | .07 | ||
|
|
Education level (university degree) | –0.837 (–1.913 to 0.238) | .13 | ||
|
|
Monthly income level (SGD 4000 and above) | 0.301 (–0.409 to 1.011) | .40 | ||
|
|
Alcohol consumption (yes) | –0.1 (–0.736 to 0.536) | .76 | ||
|
|
Smoking status (nonsmoker) | –0.72 (–2.035 to 0.595) | .28 | ||
|
|
Self-rated health (fair) | 1.811 (0.166 to 3.456) | .03 | ||
|
|
Self-rated health (good) | 0.763 (–0.479 to 2.005) | .23 | ||
|
|
Self-rated health (very good) | 0.215 (–1.026 to 1.457) | .73 | ||
|
|
UCLA score | 0.091 (0.059 to 0.124) | <.001 | ||
|
|
SHI score | 0.103 (0.043 to 0.163) | .001 | ||
|
|
PSQI score | 0.332 (0.195 to 0.47) | <.001 | ||
|
|
ESS score | 0.061 (–0.013 to 0.135) | .11 | ||
|
|
Intercept | 0.598 (–2.891 to 4.088) | .74 | ||
aUnstandardized coefficients (β) with their 95% CIs and exact P values of digital biomarkers are reported as predictors of PHQ-9 scores in multiple regression models.
bIS.st.wd: steps-based interdaily stability on weekdays.
cA currency exchange rate of SGD 1=US $0.75 is applicable.
dAC.st.15m.wd: steps-based autocorrelation with weekday data aggregated into 15-minute intervals.
eNHR.0406.cv: coefficient of variation of nighttime heart rate between 4 AM and 6 AM.