The influence of common, CNS-acting, drug prescriptions on outcomes from an intensive upper-limb rehabilitation program

Johnstone, A.; Brander, F.; Kelly, K.; Bestmann, S.; Ward, N. S.

Difficulty using the upper-limb is a major barrier to independence for many patients post-stroke or brain injury. High dose rehabilitation can result in clinically significant improvements in function even years after the incident, however there is still high variability in patient responsiveness to such interventions that cannot be explained by age, sex or time since stroke. This retrospective study investigated whether prescription of certain CNS-acting drug classes- GABA agonists, antiepileptics and antidepressants- influenced outcomes on the 3 week intensive Queen Square Upper-Limb (QSUL) programme. For 277 stroke or brain injury patients upper-limb impairment and activity was assessed at admission to the programme and at 6 months post-discharge, using the upper limb component of the Fugl-Meyer (FM), Action Research Arm Test (ARAT), and Chedoke Arm and Hand Activity Inventory (CAHAI). Drug prescriptions were obtained from primary care physicians at referral. Specification curve analysis (SCA) was used to protect against selective reporting results and add robustness to the conclusions of this retrospective study. GABA agonist prescription had a significant negative effect on upper-limb scores at admission but did not impact programme-induced improvements. There were no effects of antiepileptic drug prescriptions on either admission scores, or improvement during the programme. Antidepressant prescriptions did not impact admission scores but resulted in reduced improvement in upper-limb function, even when accounting for anxiety and depression scores. These results demonstrate that, when prescribed appropriately, GABA agonists do not impair patient's ability to benefit from rehabilitation programmes. Patients prescribed antidepressants, however, performed poorer than expected on the QSUL rehabilitation programme. While the reasons for this effect are unclear, identifying these patients prior to admission may allow for better accommodation of differences in their rehabilitation needs.