Falls and Their Associated Risks in Parkinson’s Disease Patients in Nigeria

Clinical assessments

A detailed questionnaire (interviewer administered) was used to collect socio-demographic variables (age, sex, occupation, and marital status) and relevant clinical information (date of first PD diagnosis, medication history, fall history in the last one, six, and 12 months, history of associated injury during falls and circumstances surrounding falls, static and dynamic balance, cadence and stability, and past history of hypertension and/or diabetes). PD was diagnosed independently by two trained neurologists using the UKPDS brain bank criteria [20]. A fall was defined as an event that resulted in a person coming to rest inadvertently on the ground or floor [21]. A patient was subjectively asked about fear of falling if the fall events and circumstances surrounding the fall were recorded. Cognition was assessed by using the community screening interview for dementia (CSI ‘D’) [22]. PD severity was assessed using Unified Parkinson’s Disease Rating Scale (UPDRS) criteria [23]. Cadence and stability was assessed using Timed Up and Go Test. Autonomic function was assessed using standard bedside tests (heart rate and blood pressure in response to standing). Postural hypotension was assessed using a difference of > 20 mm Hg in systolic blood pressure or > 10 mm Hg in diastolic blood pressure between standing and supine positions, respectively. Static and dynamic balance was assessed using the Tinetti Balance and Gait scale.

The Tinetti Balance and Gait test scale has a 71% sensitivity and 79% specificity to predict falls in both the elderly and PD patients [9,24]. The balance scale contains nine items with a total summation of 16 points while the gait scale contains eight items with a total summation of 12 points for a total of both 28 points for both scales. A score < 18 implies high risk, while scores between 19 and 23 imply moderate risk, and a score > 24 implies low fall risk [25]. Hypertension was diagnosed using sphygmomanometer measurements of blood pressure > 140/90 mm Hg measured at two different times or a history of antihypertensive therapy. Diabetes mellitus was diagnosed based on either a fasting plasma glucose of > 126 mg/dL or random plasma glucose of > 200 mg/dL measured on two different occasions at least 24 h apart. The Geriatric Depression Scale was used to assess depression [26].

Statistical analysis

Eighty-one consented respondents who had completed the questionnaire were analyzed. Normally distributed continuous variables were assessed using independent samples t-test, where data were not normally distributed, non-parametric methods were used. The Mann-Whitney U test for variables that were not normally distributed and Kruskal-Wallis test were used to compare ranked variables. Categorical variables were tabulated and statistically assessed for association using the χ² test or Fisher’s exact test (where the expected counts were < five per cell) to compare falling with non-falling patients. Logistic regression was performed to evaluate the fall predictors. All variables that showed association with falls in univariate analysis were included in the regression model.

Fall frequency

To the best of our knowledge, this is the first documentation of falls among PD patients in sub-Saharan Africa. The frequency of falls was 42% compared to 14.8% of age-matched healthy adults, and the median disease duration in the PD patients was 36 months. Most of the PD patients (71.6%) were on two or more anti-PD drugs. Factors responsible for falls in PD patients are multiple and most likely include similar factors associated with falls in healthy elderly patients.

The frequency of falls in our study was similar to those described in previous studies in PD patients [5,9]. In a study to assess the risk of falls in 160 PD patients, Contreras and Grandas [9] documented a 38.8% prevalence, a figure slightly lower than the finding in this study. However, a meta-analysis of six fall studies in PD patients reported fall frequencies ranging between 38% and 50% [5]. The frequency in our study lies within this range, and variations in study methodology and clinical characteristics could account for the varied frequencies.

It is difficult to speculate on cultural factors playing a very significant role in falls in PD patients because the frequency was similar to what was obtained in other environments. Factors such as special flooring (marble, tiles, and polished surfaces) that could predispose a patient to fall are absent in most traditional Nigerian homes but did not seem to have any significant effects on falling frequencies when compared to other types of homes. Additionally, there were no increases in the incidence of neuropathy, visual impairment, or medications that predispose PD patients to fall. Further studies exploring these factors should be performed.

Factors associated with falls

In this study, disease severity was associated with falls. Falling patients had significantly worse disease and longer durations when compared to non-falling patients. These findings are similar to findings by Bloem et al. [18] and Wood et al. [1], who also reported higher UPDRS motor scores in falling versus non-falling patients; therefore, this is not a predictor of falls. Postural instability was prominent in the falling patients more than the non-falling patients due to poor preparatory adjustments, abnormal postural balance, and delayed reaction time [27]. This increases the propensity for falls and leads to impaired gait-dependent activities.

A study by Contreras and Grandas[9] reported predictability of Tinetti balance test to predict falls with 71% sensitivity and 79% specificity. He confirmed the Tinetti test tool as an independent fall predictor after using a multivariate logistic regression model [9]. This is consistent with studies of gait and balance abnormalities that were carried out in other environments where gait abnormality was considered the most consistent predictor of falls [19]. However, in this study the Tinetti Balance and Gait Tool did not independently predict the risk of falls.

The frequency of falls has also been reported to have a direct correlation with age, disease severity, medication, cognitive dysfunction, orthostatic hypotension, and visual impairment [9,28]. Our study could not demonstrate age as an independent risk factor for falls. A previous study of falls both in PD patients and healthy adults had shown an association between adults > 65 years and increased falls of 30 to 40% [29]. This was most likely because most of the PD patients in that study were younger compared to other studies conducted in different environments [9,28]. Advancing age (> 70 years) has been associated with increased risk of falls due to advanced PD progression [9]. Furthermore, older age is associated with frailty and reduced muscle mass and strength. In this study, a relatively higher proportion of young onset PD patients were evaluated. This is different from previous epidemiological studies of PD in Nigeria where relatively low proportions of young onset PD patients were evaluated [30]. However, Femi et al. [31] reported an increasing older age of PD onset in the Northwestern Nigeria. These differences might be due to an inappropriate record of birth dates due to low level of literacy, shorter average life expectancy of those living in the underdeveloped and developing countries, poverty and/or poor access to health care services. Furthermore, different genetic makeups and environmental exposures of the study participants might be responsible for the observed differences [30].

A previous fall has been shown to be a significant risk factor for more falls [5]. Pickering et al. [5] reported in a meta-analysis that > 2 falls was the best predictor of more falls in PD. This might be the result of lower recovery performances in forward falls and lower muscle strength in PD patients who fall [32]. In this study, 67.7% of our PD patients had recurrent falls, out of which 44% had a fear of falling. The reported frequency of recurrent falls was higher than what was obtained by Landers et al. (51%) [16] and Dibble and Lange (55%) [23]. However, the findings in this study are similar to a prospective study of falls by Cole et al. (68%) [33]. These differences may be due to differences in methodology and characteristics of disease severity.

Adkin et al. [34] demonstrated low balance confidence scores, which is an indicator for more falls, in PD patients compared to controls [34]. Patients who fall more frequently often have a self-induced restriction of activities due to fear of more falls, thus, leading to reduced muscle strength and increased risk of more falls, resulting in poor health-related quality of life. Studies have demonstrated increased incidence of trochanteric fractures in PD patients due to adduction of arms against the trunk when falling, while older adults without PD stretched out their arms in the direction of impending fall and, thus, sustained minor injuries such as abrasion [35]. Worthy of note in this study is the predictability of fear of falling as a strong modifiable risk factor with an adjusted OR of 3.86. Thus, clinical strategies to reduce fear of falling in PD patients will reduce the frequency of falls and their health-related and economic burden. In this study, it was observed that falling PD patients sustained other injuries such as fractures and lacerations; however, Bloem et al. [18] recorded no fractures in their study but reported a high proportion of soft tissue injuries (60%) [18], a figure slightly lower than the finding in our study. These injuries may be a result of the inter-segmental stiffness and postural inflexibility observed in PD patients [33]. Thus, an exercise program that enhances flexibility is needed for PD patients.

This study has several limitations. Being a retrospective study, there was the possibility of recall bias, and subjects with cognitive impairment may not have been accurate about fall frequency. It has been said that older people tend to forget occurrences of previous falls; however, this can be improved upon by getting a fall diary to be used in a prospective study. Secondly, this was a hospital-based study, and thus, the proportion of falling patients in our study may not represent community-dwelling PD patients who are at greater risk of falls. Although the results show that fear of falling could be an independent risk factor for falls in PD patients, additional prospective studies are required to confirm if this is a cause or consequence of falling or both. Meanwhile, our findings suggest that addressing the fear of falling may help to reduce falling events in PD patients.

In conclusion, our study confirmed an increased frequency of falls among PD patients, and this frequency was shown to be multifactorial. The predictive risk factors were disease severity and duration and fear of falling. Early detection of risk factors can prevent the untoward effects of falls in PD patients. This will facilitate tailored management to suit such patients and ultimately reduce the economic health-related burden of falls in these patients.