Table 2.
Results of primary analysis that used hierarchical multiple linear regression to assess the proportion of variance in self-reported cognitive impairment (PCI) explained by demographic, medical, and psychological characteristics; appropriate statistics are given for each model. Additionally, non-standardized regression coefficients and p-values are given for each variable (coefficients of variables with p-values < 0.05 are in bold).
| Model statistics | Model 1a | Model 2b | Model 3c | |||
|---|---|---|---|---|---|---|
| R2 | 0.05 | 0.08 | 0.33 | |||
| R2 change from previous model | - | 0.03 | 0.25 | |||
| p-value of LRT compared to previous model | - | 0.27 | <0.0001 | |||
| Model variables | Coeff. (95% CI) |
p-value | Coeff. (95% CI) |
p-value | Coeff. (95% CI) |
p-value |
| Intercept | 38.19 (19.27, 57.10) | <0.0001 | 41.03 (20.66, 61.41) | 0.0001 | 9.72 (−15.64, 35.09) | 0.45 |
| Demographics | ||||||
| Age (years) | −0.11 (−0.33, 0.12) | 0.34 | −0.10 (−0.33, 0.13) | 0.40 | −0.07 (−0.27, 0.13) | 0.47 |
| Married/de facto relationship | −0.08 (−6.02, 5.86) | 0.98 | 1.18 (−4.91, 7.26) | 0.70 | 4.43 (−0.91, 9.77) | 0.10 |
| Education (years) | 0.32 (−0.48, 1.12) | 0.43 | 0.29 (−0.51, 1.10) | 0.47 | 0.26 (−0.44, 0.96) | 0.46 |
| Smoking history | ||||||
| Never (reference) | - | - | - | - | - | - |
| Previous | 1.55 (−2.55, 5.65) | 0.46 | 1.65 (−2.49, 5.78) | 0.43 | 0.84 (−2.78, 4.46) | 0.65 |
| Current | 5.58 (−4.96, 16.12) | 0.30 | 5.49 (−5.05, 16.03) | 0.31 | 1.71 (−7.47, 10.89) | 0.71 |
| Previous neurological problems | 3.80 (−1.19, 8.80) | 0.13 | 4.13 (−0.92, 9.18) | 0.11 | 0.80 (−3.62, 5.22) | 0.72 |
| Ever used antidepressants | 4.39 (0.39, 8.40) | 0.03 | 4.45 (0.42, 8.49) | 0.03 | 0.52 (−3.08, 4.11) | 0.78 |
| Medical characteristics | ||||||
| Tumor stage | ||||||
| I or II (reference) | - | - | - | - | ||
| III | 5.03 (−0.89, 10.95) | 0.10 | 3.96 (−1.15, 9.07) | 0.13 | ||
| Unknown | 1.45 (−3.21, 6.12) | 0.54 | −1.14 (−5.20, 2.92) | 0.58 | ||
| Hormone therapy | ||||||
| None (reference) | - | - | - | - | ||
| Tamoxifen, Letrozole, or Anastrozole | −1.48 (−5.92, 2.95) | 0.51 | −2.09 (−5.94, 1.76) | 0.29 | ||
| Other | 1.98 (−7.94, 11.90) | 0.69 | 4.43 (−4.18, 13.04) | 0.31 | ||
| # of chemotherapy cycles | −0.27 (−0.93, 0.40) | 0.43 | −0.01 (−0.58, 0.57) | 0.98 | ||
| Time since completion of chemotherapy (months) | −0.14 (−0.28, 0.00) | 0.05 | −0.11 (−0.23, 0.01) | 0.07 | ||
| Psychological characteristics | ||||||
| Fatigue (FACT-F) | −0.38 (−0.57, −0.19) | <0.0001 | ||||
| Anxiety and depression (GHQ) | 0.34 (−0.05, 0.74) | 0.09 | ||||
| Stress (PSS) | 1.02 (0.51, 1.53) | 0.0001 | ||||
Model 1: demographics only
Model 2: demographics + medical
Model 3: demographics + medical + psychological
Coeff.: regression coefficient; CI: confidence interval; LRT: likelihood ratio test; FACT-F: Functional Assessment of Cancer Therapy – Fatigue; GHQ: General Health Questionnaire; PSS: Perceived Stress Scale.
Note: all three models were run on the same 212 observations, where PCI and all covariates for the fullest model (Model 3) were not missing.