Analysis of pharmacology and osteoporotic fracture prevalence in Lincolnshire patients with Parkinson’s disease: bone protection, anticholinergic burden and polypharmacy

BACKGROUND

Parkinson’s disease (PD)is especially prevalent in the later stages of life and it is usually correlated with polypharmacy, medical treatment targeting the dopaminergic system alone may include up to five different compounds: L-DOPA, a catechol-O-methyltransferase (COMT) and a monoamine oxidase (MAO-B) inhibitor and a dopamine agonist. As a result of Parkinson’s disease both motor and non-motor symptoms, other drugs may be added, especially to target problems such as cognitive impairment, postural hypotension, urine incontinence, constipation and sleeping and emotional problems. Parkinson's disease is associated with substantial physical and mental co-morbidity compared to patients without Parkinsons.

It is imperative that clinical management considers the other significant illnesses that people with PD accumulate as they age in conjunction with their resilience to cope with physiological change. Multimorbidity and frailty act synergistically to heighten the risk of adverse outcomes for older people with PD. These states are associated with increased likelihood of hospitalization, polypharmacy, adverse drug effects including the anticholinergic burden of medications, drug-disease and drug-drug interactions. Patients with PD have a lower bone mineral density (BMD) than age-matched controls. Bone loss in PD is multifactorial, resulting from immobility, decreased muscle strength, and low body weight. Hyperhomocysteinaemia, an independent risk factor for osteoporosis, is common in PD, due to levodopa use, as well as vitamin B12 and folic acid deficiency. A few studies have demonstrated that treatment with bisphosphonates, vitamin D and calcium can increase BMD and reduce fractures in PD patients.

OBJECTIVES

To conduct and audit on our PD geriatric population attending a Movement Disorders Clinic carried out under the Neurology specialty during June and July 2021 in order to analyse the prevalence of cognitive impairment, postural hypotension, polypharmacy, osteoporotic fracture, anticholinergic burden and the prescription of bone protection in this population.

METHODOLOGY

Observational, transversal study. We included in this study all patients with a diagnosis of Parkinson’s disease who attended the Movement Disorder Clinic at Lincoln County Hospital between 1st June and 31st July 2021 and we later selected those aged 65 years or older. Data were extracted from the patient’s clinic letters and Summarised Care Record (SCR) in the NHS Portal. We considered polypharmacy by taking 5 or more different drugs and we excluded Parkinson’s medication from this count in order to ascertain the burden of the patient’s previous comorbidities. We considered osteoporotic fractures to be hip, vertebrae and Colles fracture. History of falls was not usually recorded and thus, it was not considered for analysis in this study given the high amount of missing data for that variable. The anticholinergic burden was calculated by using the online ACB calculator. For total dose of Parkinson’s treatment calculation the OPTIMAL online calculator was used, turning all drugs to their equivalence in Levodopa miligrams. Means (m) with standard deviations (SD) are provided for cuantitative variables and proportions in percentages (%) for cualitative variables. All analysis were carried out using SPSS v25 software.

RESULTS

55 patients were initially selected for inclusion in the study, meeting PD diagnosis criteria. Mean age was 74 years old, with a SD of 10 years. The patients had a mean of 5,5 years of PD diagnosis, with a mean dose of levodopa of 764mg (SD=488mg). From this patients, 43 met the criteria of being 65 years old or older, with a mean age of 78 years (SD=6), and PD diagnosis for 6 years (SD=6 years). 28% were female.

Mean dose of levodopa in this population was 653mg (SD=393mg). 88,4% of the sample showed polypharmacy, with a mean anticholinergic burden of 1,77 points (SD=3), 35% of them took antidepressants, 28% of them (n=14) had an osteoporotic fracture at some point, only 16,3% of the total sample had any kind of bone protection (1 bisphosphonates and calcium and vitamin D supplementation, 3 had both calcium and vitamin D and 4 had only vitamin D supplementation). Diagnosis of dementia or cognitive impairment was found in 32,6% of cases, 7% had hallucinations and a total of 30,2% of the sample presented postural hypotension, with a 58% of patients in whom this symptom was not assessed or recorded.

A sub-analysis of the population who had an osteoporotic fracture was conducted (N=12). 66,7% of this patients didn’t have any bone protection prescribed, 33,3% had a previous history of postural drops, and 58% were not assessed for this. 50% of this sample had a diagnosis of cognitive impairment or dementia.

DISCUSSION AND CONCLUSION

Parkinson’s disease affects mostly to patients over 65 years old, with usually a relatively recent diagnosis in the last 6 years, with a wide individual variability. Patients with PD in our area show a concerning prevalence of polypharmacy (88,4%), especially considering that PD specific medication was not included in the count. The anticholinergic burden was generally low to moderate, with a mean of 1,77 points in the ACB calculator, but, once again the SD was high and the burden of Parkinson’s treatment was not accounted, which points to a higher ACB in real life for this patients. Depression and dementia were very prevalent in this population (one third each of the sample showed any of them), as well as postural hypotension (30,2%). Osteoporotic fracture was also a common problem, with an alarming lack of primary or secondary bone protection: only 16,3% on the total sample had any kind of anti-osteoporotic treatment and only 1 patient from 43 had a bisphosphonate prescription. When we analysed those who had a fracture, only a third had any type of bone protection, and there was a high prevalence of postural drop and dementia. This results show that, even though PD is highly related to recurrent falls and a third of the patients also had dementia, with is an independent risk of falling, a regular falls assessment was not conducted in this population and most of the patients didn’t have their falls recorded in their SCR (even when they led to fracture).

A comprehensive geriatric assessment should be carried out in this vulnerable population, as patients with PD would benefit from an holistic view of their comorbidities, polypharmacy and other problematics derived from their neurodegenerative disorder and superadded frailty and geriatric syndromes. At this moment, considering the results of this audit; the general management of osteoporosis ,risk of falls and fractures is suboptimal in our area. A quality improvement project is needed to optimise the management of polypharmacy and primary and secondary prevention of falls and fractures in this population.