anxiety only. Figure 1 displays Kaplan–Meier (KM) survival estimates,
where the curve denotes the overall proportion of cases remaining in
remission at each time-point. Most relapse events occurred at
6-month follow-up with the least number of cases observed at
9 months. Specifically, 46.2% (n = 12) of relapse events occurred
within 3 months, 19.2% (n = 5) within 6 months and 34.6% (n = 9)
within 9 months.
For further information about the proportions of participants who
continued to show reductions, no change, and an increase in
symptoms relative to the 'end-of-treatment' at each time point,
please see Table S1.
3.3 | Predicting relapse
Table 3 shows the results of the Cox proportional hazards model
predicting time-to-relapse using multiple variables that were hypothe-
sized a priori as potential prognostic factors. This model shows that
F I G U R E 1 Survival analysis of remission and time-to-
relapse following internet-delivered cognitive-behavioural
therapy (iCBT). Note: N = 89 at end-of-treatment; 77 at
3 months; 72 at 6 months, 63 at 9 months
T A B L E 3 Cox proportional hazard
model predicting time-to-relapse
Hazard ratio SE Z P 95% CI
End-of-treatment
Age 0.940 0.024 0.258 0.008 0.898 to 0.984
Gender 2.981 0.779 1.402 0.161 0.648 to 13.724
Ethnicity 2.009 0.645 1.082 0.279 0.568 to 7.106
Long-term condition 3.936 0.606 2.261 0.024 1.201 to 12.903
Employment status 1.680 0.590 0.880 0.379 0.529 to 5.430
MINI dep and/or anx diagnosis 0.758 0.613 0.454 0.651 0.228 to 2.519
Residual symptoms (PHQ-9) 0.814 0.579 0.356 0.772 0.262 to 2.530
Residual symptoms (GAD-7) 2.937 0.865 2.258 0.046 1.019 to 8.466
Baseline to end-of-treatment change
Medication (reference never took medication)
Always on medication 1.904 0.614 1.049 0.295 0.571 to 6.347
Started taking medication. 0.412 1.193 0.744 0.457 0.040 to 4.266
Stopped taking medication. 1.800 0.685 0.858 0.391 0.470 to 6.888
Usage (baseline to end-of-treatment)
Number of logins 0.946 0.026 0.154 0.878 0.946 to 1.049
Length of platform use 0.997 0.001 1.000 0.573 0.997 to 1.002
Number of reviews 0.679 0.176 0.239 0.811 0.679 to 1.353
Usage (end-of-treatment to 9 months post-treatment)
Number of logins 1.065 0.097 0.649 0.515 0.881 to 1.288
Length of platform use 0.966 0.006 0.600 0.519 0.985 to 1.008
PALACIOS ET AL. 1773
