Falls and, eventually, fall-related injuries are a very serious problem for persons with Parkinson’s disease (PD): approximately 60% of them report at least one fall each year, and two-thirds of them report recurrent falls, with double the rates of general older population. Falls are associated with escalating healthcare costs and are major contributors to reduced health-related quality of life in PD patients. Some of the falls risk factors in PD, such as freezing of gait (i.e., an episodic inability to initiate or continue walking), balance deficits, mobility impairments, and lower-limb muscle strength deficits, have the potential to be modified with exercise or pharmaceutical interventions. Thus, an increasing number of studies were designed to analyze different interventions to prevent falls in PD, but what is the evidence of their effects? 

A Cochrane review by Allen et al. has recently addressed this issue. Their search included only trials where participants with idiopathic PD who had been diagnosed by the UK Parkinson’s Disease Society Brain Bank criteria, or by a clinical definition, were randomly assigned either to the selected intervention or to a control group (randomized controlled trials, or RCTs). The considered interventions included exercise, medication, fall-prevention education, and exercise plus education combined, while interventions that aimed to reduce falls due to syncope (e.g., dizziness and fainting) were excluded. The addressed outcomes were the rate of falls and the number of people who fell at least once. Secondary outcomes included fall-related fractures, quality of life, adverse events, and economic outcomes. 

The review included 32 RCTs with 3,370 participants published up to July 16, 2020. Of these, 25 studies with 2,700 participants were exercise trials with different exercise programs, 12 of them comparing exercise with an intervention not thought to affect falls. Three studies with 242 participants were in medication trials. One study with 53 participants was an education trial. Three studies with 375 participants were exercise-plus-education trials. Overall, the exercise and exercise-plus-education studies included people with mild to moderate PD. As to the quality of the evidence, all studies had a high or unclear risk of bias in at least one area. Exercise trials provided moderate-certainty evidence that exercise reduces the number of falls by around 26% and slightly reduces the number of people experiencing one or more falls by around 10%. There also is low-certainty evidence that exercise slightly improves health-related quality of life immediately after the exercise program, but it is uncertain whether it reduces fall-related fractures. As to pharmacological interventions, all three studies investigated cholinesterase inhibitors, which address the central nervous system cholinergic neuron loss associated with PD and may reduce falls by enhancing cognitive and attentional resources and/or reducing gait variability contributing to falls. These studies provided low-certainty evidence that a cholinesterase inhibitor, compared with placebo medication, may reduce the rate of falls by around 50%; however, the same medication may also increase the number of non-fall-related adverse events, though predominantly mild or transient, by around 60%. The one study comparing education alone with a control intervention provided very low-certainty evidence that the intervention makes little or no difference in the number of people who fell at least once, while three studies that compared exercise-plus-education with a control group provided very low-certainty evidence that this combined intervention makes little or no difference to the number of falls, the number of people sustaining fall-related fractures, or health-related quality of life and low-certainty evidence that it may make little or no difference to the number of people experiencing one or more falls. Overall, few studies included economic measures, and those evaluations used different methods, perspectives, time horizons, and cost items, making it difficult to compare economic results across studies and intervention types.  

The authors thus conclude that exercise interventions probably reduce the rate of falls, and probably slightly reduce the number of people falling in people with mild to moderate PD. However, further high-quality research is needed to determine the relative impact of different exercise programs on falls and how disease severity may modulate them. As to pharmacological interventions, cholinesterase inhibitors may reduce the rate of falls, but their effect on the number of people falling is uncertain, and the decision to use these medications needs to take into account the risk of non-fall-related adverse events. Both the effects of medication and of fall-prevention education interventions, whether or not combined with exercise, also deserve further investigation. 

Francesca Cecchi