Tool for longitudinal monitoring of medicine-related symptoms in older people: a feasibility study

Background: Older adults are vulnerable to medicine-related harm due to age-related changes in pharmacokinetics and pharmacodynamics. 

Aim: The aim of this study was to adapt and test a tool for longitudinal monitoring of medicine-related symptoms in older adults. 

Method: The PHArmacotherapeutical Symptom Evaluation-20 tool was adapted from a four-point to an 11-point scale (PHASE-20–Australian version) and administered to residents at the initial interview and again at the 4-week follow up in an aged-care facility, located in South Australia, Australia. The Edmonton Symptom Assessment Scale (ESAS) tool was used as a comparator to evaluate how the adapted tool tracks symptoms overtime. Symptoms reported using the PHASE-20–Australian version were compared with adverse effects of medicines in use listed in the Australian product information. The test–retest reliability of the adapted tool was also evaluated. Ethical approval was granted by the University of South Australia Human Research Ethics Committee (Reference no: HREC205098) and the study conforms to the Australian National statement on ethical conduct in human research. Informed consent was obtained from all participants via the distribution of project information sheets and completion of written consent forms. 

Results: Nineteen residents (mean age ± standard deviation [84.4 ± 8.0 years]) completed the initial assessment and 17 completed the follow up. Seventy-two percent of the symptoms reported using the PHASE-20–Australian version matched the common or very common adverse effects listed in the Australian product information for the medicines used by the residents. The PHASE-20–Australian version showed a strong positive correlation with ESAS scores (rho = 0.744, p < 0.001). Changes in PHASE-20–Australian version scores correlated moderately to strongly with changes in ESAS scores (rho = 0.658, p < 0.004). The adapted tool had acceptable test–retest reliability (intraclass correlation coefficient = 0.738). 

Conclusion: The score of PHASES-20–Australian version correlated well with a tool validated for longitudinal monitoring of symptoms and demonstrated acceptable test–retest reliability. Further studies are needed to confirm its validity for longitudinal monitoring of medicine-related symptoms.