Our study showed that 71.8 % of family caregivers of frail older adults with multimorbidity experienced caregiver burden. In the bivariate analysis, there was statistically significant difference between the proportion of caregiver burden experienced, for care recipients in the CFS 5 (mildly frail) and CFS 6 (moderately frail) groups(p=0.02), as well as care recipients in the CFS 5(mildly frail) and CFS 7 (severely frail) groups (p=0.03). There was very weak correlation between the number of chronic conditions that a care recipient with multimorbidity had and the respective caregiver burden. The Spearman’s rank correlation coefficient was 0.16 (p=0.03). However, after adjusting for other factors, these associations were not statistically significant anymore. After multivariable logistic regression, the increased time spent caregiving per week was associated independently with primary family caregivers’ perception of burden (OR 1.04, 95%CI: 1.01,1.08, P=0.01). We also found that non-Chinese primary family caregivers when compared to Chinese primary family caregivers had less perceived burden (OR 0.34, 95%CI: 0.13,0.93, P=0.03).
Our finding of 71.8 % of family caregivers of frail older adults with multimorbidity experiencing caregiver burden was higher than similar studies conducted overseas where about 60% of informal caregivers perceived burden.16,20 The higher percentage of our local caregivers perceiving burden may be explained due to societal norms with emphasis on filial piety and family members being involved in caregiving duties.27 In addition, urbanisation has produced increasingly smaller families, thus reducing the number of available family caregivers and limiting the extent to which the burden can be shared between family members.28
In our study, bivariate analysis in Table 3a showed an association between the frailty status of care recipients and the burden perceived by their respective primary family caregivers (p= 0.03). Table 3b showed the Bonferroni correction that was performed to see which of the comparisons were statistically significantly different from each other after adjusting the p value to account for multiple comparisons. Interestingly, none of the comparisons was found to be statistically significant after the correction. The Bonferroni correction is commonly employed to reduce type I error (i.e., rejecting the null hypothesis when the null hypothesis is true) when multiple comparisons were conducted.29 However, using the Bonferroni correction may be too conservative and resulted in type II error (i.e. accepting the null hypothesis when the null hypothesis is false).Furthermore, type I errors cannot be decreased (the aim of Bonferroni adjustments) without inflating type II errors (the probability of accepting the null hypothesis when the alternative is true).30 For this instance, we disregarded the use of the Bonferroni Correction and accepted the association between the frailty status of care recipients and the burden perceived by their primary caregivers as significant. However, when the different levels of frailty status were included in the multivariable logistic regression after adjusting for other factors, the frailty status of care recipient was not associated with caregiver burden anymore. Similarly, a study by Aggar et al. found that caregivers of care recipients deemed severely frail (Fried Frailty Status >3) did not differ from caregivers of care recipients deemed mildly frail (Fried Frailty Status = 3) in terms of time demands and self-esteem.10,31
There was a very weak correlation between the number of chronic conditions care recipients had and caregivers’ perception of burden on bivariate analysis. The Spearman’s rank correlation coefficient was 0.16 (p=0.03). When this variable was put into the multivariable logistic regression, the odds for the increase in the number of chronic conditions that care recipients had was positively associated with caregiver burden (OR 1.36, 95%CI: 0.98,1.89, P=0.06) but this was not statistically significant. A study in Egypt on 186 family caregivers of older adults also found no significant association between care recipients’ number of chronic diseases and caregivers’ burden.32
Notably, 33.5% of care recipients in our study had dementia. Although it has been shown that care recipients with dementia increases caregiver burden,33,34 our study showed otherwise. We did not find a significant association between the presence of dementia and caregivers’ perceived burden. This could be because care recipients who had dementia in our study were early or mild cases whereas those in the literature had significant numbers who exhibited behavioral and psychological symptoms of dementia.
One of the findings from our study was that more time spent caregiving per week was associated with caregivers’ perception of burden. This finding is similar to other studies. A cross-sectional study of 200 community residing patients in China, showed that longer hours of caregiving corresponded with an increase in caregiver burden experienced.35 Additionally, other studies done in Turkey and the Netherlands reported that caregivers who invested more time in caregiving had increased worry and higher burden.11,13
The other finding in our study was that ethnicity of the caregiver was an independent factor that was associated with caregiver burden amongst primary family caregivers of frail older adults with multimorbidity. Specifically, in our study, Chinese caregivers had almost three times the odds of perceiving burden when compared to the non-Chinese caregivers. This is similar to a study of 385 caregivers of older people who attended a community clinic in Malaysia, which found ethnicity to be an independent factor that was associated with caregivers who were burdened 36. In this study and another, also in Malaysia, a country with a multi-ethnic composition, Chinese caregivers were found to have a higher level of burden. 36,37 A possible explanation for this finding could be because in the Chinese family, the obligation to care for a dependent elder is primarily influenced by cultural values of family responsibility 38 and filial obligation as one of the potential motivating factors in a caregiving relationship.39 In Taiwan, which has a largely homogenous Chinese population, coupled with the Chinese tradition of filial piety, caregiver burden has become a pervasive problem in Taiwanese people, especially women, who are expected to assume the role of primary caregiver.40 Likewise, in Singapore where our study was conducted, the Chinese primary family caregivers may be burdened by similar concepts and values of family responsibility and obligation.
Finally, studies on the impact of relationship to care recipient on caregiver burden found mixed results. While one study by Oldenkamp et al. did not find the type of care relationship to be signficant13, others found that children caregivers, particularly daughters and daughters-in-law had higher burden.16,41,42 Our study did not find an association between relationship to care recipient and caregiver burden. Our study also did not find any association between gender of caregiver and caregiver burden, which is consistent with current literature.43
Strengths and Limitations
This is the first study conducted in Singapore looking at caregivers of frail older adults with multimorbidity. Reporting bias was minimised as this interviewer-administered study was carried out by a small team of three interviewers who have standardised the interview methods prior to the start of the research project.
One of the limitations of our study is the use of convenience sampling. However, we minimised potential bias by inviting all eligible caregiver-care recipient dyads who attended the clinic during the recruitment period. There may also be non-response bias as the participants who consented to take part in the study may differ from those who do not. However, this is also perceived to be low as our response rate was high at 91.7%.