This is the first study to demonstrate that HNC caregivers who perceive patients’ QOL more negatively than patients themselves after treatment completion have more significant psychological distress. It was found that roughly one-third of caregivers viewed the social-emotional QOL, and almost half viewed the physical QOL of their patients more negatively than patients themselves.
Disagreement regarding physical QOL and disagreement regarding social-emotional QOL were not significantly associated with caregiver anxiety in our multivariate analysis (Table 4). However, disagreement regarding physical QOL and disagreement regarding social-emotional QOL were both significantly associated with caregiver depression (Table 5). On average, caregivers who agreed with patients regarding physical QOL or social-emotional QOL reported PHQ-8 scores that indicated no symptoms of depression. On the other hand, caregivers who disagreed with patients regarding physical or social-emotional QOL reported PHQ-8 scores more than 6 points higher than caregivers who agreed after controlling for covariates. The fact that an association was found with depression but not anxiety is consistent with prior research, including the findings of Lee et al. who found that 6 months after diagnosis of HNC, 12.9% of caregivers had depressive disorders while 0% had anxiety disorders .
It is worth noting that among patient-caregiver dyads that disagreed regarding social-emotional QOL (i.e., when caregivers reported scores at least 7 points lower than patients), the actual mean difference in social-emotional QOL scores reported by patients and caregivers was 17.83. When dyads disagreed regarding physical QOL the mean difference in physical QOL scores was 16.51. Future research involving longitudinal studies with larger cohorts should explore if there is a range of cutoffs that define significant differences in perception of QOL and if using different cutoffs may strengthen the association between differences in perception of QOL and caregiver distress.
Our findings are in line with those of Deschler et al., who reported that among a cohort of 14 patient-caregiver dyads, 45% of caregivers rated patient QOL lower using the SF-36 survey 6 months post-operatively . As for the association we observed between differences in perception and caregiver distress, our findings are consistent with the literature in other fields. In a 2016 study of couples living with non-small cell lung cancer, Lyons et al. reported that, on average, spouses rated patients’ fatigue more severely than patients themselves. Moreover, spouse mental health was worse when couples had disparate appraisals of patients’ fatigue . Similarly, in a 2015 study of stroke survivors and their spouses, McCarthy et al. reported that 43% of spouses rated survivor physical-functioning (as measured by the Stroke Impact Scale) significantly more negatively than survivors themselves. Moreover, spouses who perceived their patients’ physical function more negatively than patients themselves were significantly more likely to experience greater depressive symptoms as measured by the PHQ8 , which was also identified in our study. Indeed, this association is heavily supported because it does not appear to depend on the instrument used to measure physical function (our study used the UWQOL while McCarthy et al. used the Stroke Impact Scale). Furthermore, Miaskowski et al. reported on patient-caregiver dyads going through cancer treatment who were asked to rate the severity of patients’ pain. According to the authors, caregivers in “non-congruent dyads” had significantly higher depression scores and caregiver strain scores than those in “congruent dyads.”  This finding is in line with our study, especially given that “pain” is one of the elements included in the social-emotional QOL score of the UWQOL questionnaire.
We considered multiple explanations for the association between differences in perception of QOL and caregiver distress. For one, we wonder if distressed caregivers are inherently more likely to have more negative views of patient QOL than patients themselves. Simply put, existing literature suggests that HNC caregivers endure higher levels of psychological distress than the general population  and patients themselves [1, 12, 13]. This seems intuitive given the burden of the caregiving role. Caregiving responsibilities often come at the expense of self-care [9, 10], and the challenge is made even more difficult by the sense of loss regarding personal freedom, the appearance and health of a loved one, and overall happiness . It is conceivable that these factors elicit caregiver depression which, in turn, negatively skews caregivers’ perceptions regarding patient QOL. As such, relatively negative views of patient QOL may be an accurate indicator of overall caregiver distress.
The idea that differences in perception of QOL indicate generalized distress is supported by existing literature, demonstrating that caregivers have more negative views than patients in other areas. For instance, as reported by Hodges et al., fear of recurrence is typically greater among caregivers than patients during the post-treatment period . Moreover, greater fears of recurrence are predictive of greater future psychological distress. Additionally, Richardson et al. report that caregivers express greater concern about the illness at the time of HNC diagnosis and believe that it will last longer than patients [36, 37]. Simply put, we wonder if these relatively negative perceptions collectively indicate a generally negative outlook that suggests depressive symptoms, which are highly common among HNC caregivers. Future studies could elaborate on this possibility by determining if caregivers with negatively skewed perceptions of one aspect of the illness experience are more likely to have similarly negative views on others and if depressed caregivers are more likely to have negatively skewed views on all topics.
Based on this theory, we propose screening for discrepancies in perception as a way of identifying distressed caregivers. Specifically, comparing caregivers’ perceptions of patients’ QOL against patients’ perceptions is prudent given the existence of a validated HNC QOL instrument (UWQOL) that can quantify and objectively indicate significant disparities in perception. In practice, every time a patient completes the UWQOL to assess for changes in their QOL caregivers could be asked to do the same to screen for distress. At present, referrals for therapy as needed are a standard part of care for HNC survivors . It stands to reason that routine assessment of mental health and subsequent referrals for caregivers are warranted as well.
We also consider the possibility that differences in perception of patient’s QOL signify an unmet need for communication between patients and their caregivers. In a series of semi-structured interviews, Badr et al. reported that communication was often diminished because patients felt poor or wanted to shield their partners from cancer-related concerns . Outside of HNC, such failures at communication have been shown to have deleterious consequences for caregiver well-being. In a study of 193 severely ill patients (i.e., suffering from cancer, COPD, or congestive heart failure) and their caregivers, 39.9% of caregivers desired more communication with their patient regarding their needs and goals for treatment, and those who complained of difficulties communicating had higher caregiver burden (measured by Zarit Burden Inventory) . This explanation would underscore the utility of interventions that target caregivers and their patients together. Specifically, medical providers could facilitate discussions in which patients and caregivers both express their thoughts regarding the treatment/recovery process and share how their own well-being is being affected. By making this a part of routine follow-up appointments, providers can take an active role in ensuring long-term communication between patients and caregivers, which may positively impact caregiver distress.
It is worth noting that not all of our caregivers disagreed with their patients regarding patient QOL. Indeed, a majority of dyads were concordant in their opinions which naturally begs the question, are there particular characteristics that make caregivers more likely to negatively perceive patients’ QOL? This particular study examined a number of clinical and demographic variables, though there are undeniably other sources of heterogeneity among patient-caregiver dyads, including family dynamics and specific caregiver responsibilities. Soliciting the specific opinions and experiences of disagreeing caregivers in semi-structured interviews like those conducted by Badr et al.  may be an effective way of delineating predisposing characteristics.
Limitations of this study warrant discussion. Most notably, the sample size for this study limits its ability to determine significance, and future studies should reexamine our findings with larger cohorts. Moreover, interrelationships with variables that were not examined in this study possibly exist.