In this large population-based study, perceived health and psychological well-being were significantly poorer among those with diabetes and a history of foot ulcer than among those without diabetes. Comparing the diabetes groups, perceived health was significantly worse among those with a history of foot ulcer, while no differences between the groups were found for levels of anxiety, depression or psychological well-being.
HUNT2 is to our knowledge the largest, non-selected population-based study of diabetes-related foot ulcers, including over 60,000 participants. Three outcome measures – anxiety and depression (HADS), psychological well-being and perceived health – allow for a broad view of the studied field. Although self-reported diabetes was validated by blood tests, it is nevertheless likely that some subjects with diabetes were included in the non-diabetic group. Among those without known diabetes, a total of 62,757 delivered a non-fasting venous blood sample for glucose measurement. Of these, 217 persons had glucose levels above 11 mmol/l, and this group was followed up separately, but not included in the group with known diabetes due to uncertainty as to whether this was a permanent condition. Therefore it might be that the number of subjects classified as having diabetes based on self-report is underestimated. Although history of foot ulcer in people with diabetes is self-reported and has inherent limitations, it was not feasible to clinically validate the diagnosis in this large epidemiological study. Even though some participants may erroneously have reported other types of ulcers, such as venous leg ulcers, the term foot ulcer (fotsår) is probably less ambiguous in Norwegian than in English. Not including data on neuropathy and nephropathy in the models could be seen as a limitation. However measurement of neuropathy and nephropathy was not feasible in this large epidemiological study.
Both diabetes groups reported worse perceived health than the non-diabetic group. This is in accordance with results from other studies indicating that perceived health is affected by chronic illness such as diabetes, and people with diabetes typically rate their health worse than non-diabetic people [19
]. Perceived health is thought to reflect the underlying disease burden [20
] and has been shown to be a good predictor of mortality [18
]. In our study, perceived health was significantly worse among those with a history of diabetic foot ulcer than among those without. The association between a foot ulcer and health has also been shown in a previous study among people with current diabetic foot ulcers [5
]. In that study Ribu and collaborators showed that those with current foot ulcers have poorer health status than diabetic patients without foot ulcers and the general population. Another study found that those with primary healed ulcers had better perceived health than those with current ulcers [4
]. Our results indicated that a history of foot ulcer had an independent impact on perceived health over and above the underlying diabetes itself.
Previous studies [21
] have found that there may not be enough focus on the prevention of foot ulcers in diabetic persons. By assessing perceived health, health care professionals may identify vulnerable patients with diabetes and might offer these patients more individual support and an appropriate foot care program. Future studies should examine whether perceived health is a predictor of excess mortality in patients with a history of foot ulcer.
The two diabetic samples reported poorer psychological well-being than the non-diabetic sample. Although the presence of diabetes-related complications has been reported to be associated with psychological distress [23
], we are not aware of published studies including participants with a history of foot ulcer and a non-diabetic comparison group. Studies using focus group interviews have found that people with a current foot ulcer report emotions of frustration, anger and guilt about the possible development of new ulcers and threat of amputations [25
]. Results from our study indicate that such feelings may persist after the ulcer has healed, as our measure of psychological well-being incorporates such aspects as life satisfaction, vigour, calmness and cheerfulness. In HUNT2, a history of foot ulcer, stroke and angina pectoris had similar associations with psychological well-being and perceived health, indicating that the burden of a history of foot ulcer is comparable to the perceived burden of stroke and angina pectoris.
Our findings of higher rates of depression in people with diabetes than in non-diabetic participants are in agreement with results from previous studies [26
]. Ismail [6
] has shown that up to one-third of people with their first diabetic foot ulcer suffer from clinical depression. In our study, the proportion with a history of foot ulcer and symptoms of depression (HADS-D ≥ 8) was lower (18.8%). One possible reason may be that our question was about a history of foot ulcer and not a current foot ulcer. Among subjects with diabetes, those who also have complications are more likely to have depressive disorders than those who do not [28
]. This was confirmed for complications such as cardiovascular comorbidity or eye problems due to diabetes, which had an independent impact on depression. The lack of an independent association between diabetic foot ulcers and depression was in line with Vileikyte et al [29
]. Others, however, have reported that depressive symptoms are associated with impaired healing and recurrence of ulcers in elderly type 2 diabetic patients [30
]. In addition, increasing evidence points to the importance of assessing diabetes-specific and/or ulcer-specific distress rather than just generalized distress [31
]. Neuropathy and its symptoms, including pain, loss of feeling, and especially unsteadiness, seem to be particularly important determinants of depression [29
Diabetes-specific variables such as insulin use, diabetes duration and the level of HbA1c
were not significantly associated with perceived health or psychological distress in the multivariate analyses among diabetic persons with or without a history of foot ulcer. This is in accordance with the study of Ismail [6
] who found no association between depression and glycaemic control among people with their first foot ulcer. In previous studies among persons with diabetes, obesity was associated with a higher likelihood of depression [34
]. This was confirmed in the present study, where obesity had an independent association with depression, poorer psychological well-being and poorer perceived health. Thus, health care personnel should pay attention to the possibility of psychological distress in obese diabetic patients.