Table 2.
Analyses of predictors of complete loss to follow-up.
| Predictor variable | Lost to follow-up n = 50 | Not lost to follow-up n = 359 | Odds ratio (95% confidence interval) | Area under ROC curve, or sensitivity and specificity | |
|---|---|---|---|---|---|
| Hypothesized predictors | |||||
| Number of absencesa | Median (25%, 75%) | 2.0 (0, 5) | 0 (0, 1) | 1.78 (1.49-2.12) | 0.723 |
| 95% CI | 1 to 4 | 0 to 1 | |||
| Contactb | Yes | 18 | 188 | 0.51 (0.28-0.95) | 0.64, 0.52 |
| No | 32 | 171 | |||
| Other analysesc | |||||
| Aged | Mean ± SD | 42.5 ± 14.1 | 48.1 ± 14.0 | 0.97 (0.95-0.99) | 0.623 |
| 95% CI | 38.6 to 46.4 | 46.6 to 49.5 | |||
| Sex | Female | 40 | 285 | 1.04 (0.50-2.17) | 0.20, 0.79 |
| Male | 10 | 74 | |||
| Schoolinge | High | 23 | 185 | 0.80 (0.44-1.44) | 0.54, 0.52 |
| Low | 27 | 173 | |||
| Marital statusf | Together | 21 | 194 | 0.61 (0.34-1.11) | 0.58, 0.54 |
| Not together | 29 | 164 | |||
| Self-efficacyg | Mean ± SD | 32.2 ± 12.5 | 32.2 ± 12.2 | 1.00 (0.98-1.02) | 0.502 |
| 95% CI | 28.7 to 35.7 | 31.0 to 33.5 | |||
| > 3 diagnoses | With | 1 | 24 | 0.29 (0.04-2.15) | 0.98, 0.07 |
| Without | 49 | 335 | |||
| Allergic disease | With | 15 | 90 | 1.28 (0.67-2.45) | 0.30, 0.75 |
| Without | 35 | 269 | |||
| Connective tissue disease | With | 3 | 64 | 0.29 (0.09-0.98) | 0.94, 0.18 |
| Without | 47 | 295 | |||
| Diabetes | With | 6 | 59 | 0.69 (0.28-1.70) | 0.88, 0.17 |
| Without | 44 | 300 | |||
| Vascular disease | With | 10 | 55 | 1.38 (0.65-2.93) | 0.20, 0.85 |
| Without | 40 | 304 | |||
| Rheumatic disease | With | 4 | 43 | 0.64 (0.22-1.86) | 0.92, 0.12 |
| Without | 46 | 316 | |||
| Fibromyalgia syndrome | With | 5 | 27 | 1.37 (0.50-3.73) | 0.10, 0.92 |
| Without | 45 | 332 | |||
| Cardiovascular disease | With | 0 | 24 | 0h | 1.00, 0.07 |
| Without | 50 | 335 | |||
| Cancer | With | 2 | 21 | 0.67 (0.15-2.95) | 0.96, 0.06 |
| Without | 48 | 338 | |||
| Asthma | With | 3 | 18 | 1.21 (0.34-4.26) | 0.06, 0.95 |
| Without | 47 | 341 | |||
| Depression | With | 4 | 13 | 2.31 (0.72-7.40) | 0.08, 0.96 |
| Without | 46 | 346 | |||
| Pulmonary disease | With | 3 | 10 | 2.23 (0.59-8.39) | 0.06, 0.97 |
| Without | 47 | 349 |
For the number of absences, the table shows medians, 25th & 75th percentiles, and 95% confidence intervals.
For the other two continuous variables, the table shows means ± SDs, 95% confidence intervals, and areas under ROC curves.
For each categorical variable, the table shows numbers of people in each category, odds ratio and its 95% confidence interval, sensitivity, and specificity.
a Number of absences from program sessions; minimum = 0, maximum = 6. Odds ratio from simple logistic regression.
b No: did not have in-person contact with one of the researchers; yes: did have contact, once, at the time baseline data were collected.
c Analyses of predictors studied previously or suggested during peer review.
d Age in years. Odds ratio from simple logistic regression.
e Low: high school or less; high: college or more.
f Together: living together; not: all others
g Score on a 0-to-60 scale measuring self-efficacy to manage symptoms; odds ratio from simple logistic regression.
h Because no people with cardiovascular disease were completely lost to follow-up, there was complete separation in the "complete loss to follow-up" category. For a conservatively-biased estimate, changing the 0 to 1 and the 50 to 49 would yield an odds ratio of 0.29 (0.04-2.15).