Table 3 Multivariable regression models assessing differences in health care utilisation of the comparative patient groups, as measured over a one year follow-up period
Outcome variableRegression modelIRR* (95% CI)p-value
Number of subsequent visitsNegative binomial regression1.19 (1.01–1.41)0.038
Number of referralsNegative binomial regression0.97 (0.71–1.32)0.845
Number of investigationsNegative binomial regression1.68 (1.26–2.24)>0.001
  • Note: IRR = incidence rate ratio, CI = confidence interval.

  • * Fatigue symptom patient group designated as the reference group.

  • IRR adjusted for matched variables (age, age2, sex, practice number, provider number and quarter of index visit) and remaining covariates (number of previous and co-occurring chronic morbidities, number of previous and co-occurring psychosocial morbidities and previous care-seeking frequency).