Influence of age on pain intensity, functional impairment and health-related quality of life before and after surgery for lumbar degenerative disc disease.

BACKGROUND: Demographic changes will lead to an increase of elderly people in our population and consecutively to a higher prevalence of patients suffering from degenerative disc disease (DDD). The goal of this study was to investigate age-related differences in pain intensity, subjective and objective functional impairment and health-related quality of life (HRQoL) in patients with lumbar DDD.

METHODS: In a prospective two-center study, back and leg pain intensity (visual analogue scale (VAS)), functional impairment (Oswestry Disability Index (ODI), Roland-Morris Disability Index (RMDI)) and HRQoL (EuroQol-5D (EQ-5D), Short-Form (SF12)) were collected for consecutive patients undergoing lumbar spine surgery. Objective functional impairment (OFI) was measured using the Timed Up and Go (TUG) test. Adjusted partial correlation was used to correlate age to each scale preoperatively, as well as to the postoperative improvement at six weeks.

RESULTS: A total of n=377 patients (161 females, 42.7%) with a mean age of 58.5 years (SD 15.7, range 18.0-93.7) were included. Unadjusted TUG test raw times naturally increased with age, whereas the age-effect on standardized OFI T-scores was close to zero in patients with a lumbar disc herniation (LDH; r=-0.0666, p=0.367) or lumbar spinal stenosis (LSS; r=-0.0134, p=0.879). There was a weak correlation between age and higher ODI (LDH: r=0.1289, p=0.089; LSS: r=0.1975; p=0.027), lower EQ-5D (LSS: r=-0.1824, p=0.042) and higher RMDI by trend (LSS: r=0.1679, p=0.061). The correlation between age and postoperative improvement was negative on the VAS for back pain (LDH: r=-0.3189, p=0.026), VAS for leg pain (LDH: r=-0.3656, p=0.009) and RMDI by trend (LSS: r=-0.2004, p=0.069), as well as positive on the EQ-5D index (r=0.2412, p=0.011), indicating that younger patients showed better improvement. Due to in-group heterogeneity, no age-effect could be calculated for patients scheduled for surgical fusion.

CONCLUSIONS: The influence of age on subjective and objective measures of pain, functional impairment and HRQoL is limited for patients with LDH and LSS, but suggests an age-dependent increase of functional disability. Younger patients generally showed greater postoperative improvement at six weeks than older patients.