Sleep Quality in Patients with Diabetic Foot Ulcers

  Abstract: Objective. To assess sleep quality in a population of patients with diabetic foot ulcers. Methods. This was an exploratory, descriptive, cross-sectional study. The Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality in 60 patients with diabetes mellitus and foot ulcers. Results. Seventeen (28.3%) patients had a global PSQI score less than 5, indicating that they were good sleepers, while 43 (71.7%) patients were considered poor sleepers. The patients reported going to bed between 9:00 pm and 11:00 pm (n = 40, 66.70%), taking from 16 minutes to 30 minutes to fall asleep (n = 25, 41.70%), and waking up after 4 hours to 5 hours of sleep (n = 40, 66.70%). Conclusion. Patients with diabetic foot ulcers have poor sleep quality.

Introduction

  Globalization and changes in the demographic transition process have increased life expectancy, making the population susceptible to some age-related nontransmissible diseases, which constitutes a public health problem.¹ Diabetes mellitus is a heterogeneous syndrome with multifactorial etiology, resulting from lack of insulin or the inability of the body to effectively respond to insulin.² According to the World Health Organization and the International Diabetes Federation, approximately 160 million people worldwide had diabetes mellitus in 2002, and projections indicate that 300 million people worldwide will have the disease by 2025.³ In Brazil, there are about 5 million individuals with diabetes, half of whom do not know they have the disease; type 2 diabetes accounts for 90% of all these cases.⁴ The cost of diabetes mellitus corresponds to 2.5% to 15% of the annual health budget, depending on its prevalence and the level of sophistication of the available treatment. The direct cost of diabetes was estimated to be $3.9 billion dollars in Brazil, $0.8 billion dollars in Argentina, and $2 billion dollars in Mexico.⁵   Diabetic foot ulcers (DFU) are among the most common complications of diabetes. They are caused by vascular and/or neurological changes typically associated with diabetes and are a chronic complication that occur, on average, 10 years after the onset of diabetes.^6,7 Diabetic foot uclers are a leading cause of hospitalization of patients with diabetes and have become a public health problem.1 Moreover, patients with DFU may require a lower-limb amputation, which may lead to a high social and economic cost associated with early retirement, disability, and avoidable death.^8-10 Diabetic foot ulcers have a large impact on quality of life and often impede normal daily activities, including changes in lifestyle and sleep quality.⁹ It is important to invest in the prevention of diabetic complications to reduce the impact of lack of adequate sleep on the physical and mental health status of patients.⁹   Issues such as health and sleep quality have attracted the interest of investigators attempting to understand the multidimensionality of sleep quality in sick patients, allowing a differentiated approach to care management.¹¹ Sleep is defined as a complex physiologic state that requires full brain integration. During sleep, there are changes in the physiological and behavioral response, such as decreased motor activity and an increased threshold for response to external stimuli. Sleep is also characterized by an interrupted state organized in phases which have different and specific electroencephalographic tracings.¹² Somnolence affects 2% to 5% of the population worldwide; it results in decreased school and work performance and cognitive and neuropsychological changes.¹³ It also has a negative impact on family and social relations.¹³ Estimates show that 2% to 41% of accidental injuries are caused by somnolence or fatigue, resulting in high financial costs and loss of life.¹⁴ Among the requisites for a normal life is the ability to get a good night’s sleep, which can improve quality of life and self-esteem, and prevent depression.   The objective of this study was to assess the quality of sleep in patients with DFU.

Methods

  This exploratory, descriptive cross-sectional study was approved by the Research Ethics Committee of the Universidade Federal de São Paulo (UNIFESP), Brazil. All patients provided written, informed consent prior to their inclusion in the study and anonymity was assured. The data were collected between December 2008 and December 2010.   This work on sleep quality in patients with DFU is part of a broader study aimed at understanding the many facets of sleep quality in patients with conditions that may interfere with sleep. This understanding will allow for differentiated approaches to treatment and the ability to tailor care to meet the specific needs of patients. The initial focus of the main study was to assess sleep quality in patients with ulcers in the lower extremities, including venous leg ulcers¹⁵ and DFU, and to evaluate the influence of each type of ulcer on the quality of sleep of these patients. Some factors that may affect sleep quality in patients with DFU, such as poor glycemic control, nocturnal hypoglycemia, and nocturia, differ from those that affect patients with venous leg ulcers.^16,17 Thus, the author conducted separate studies for each type of ulcer.   Sixty patients with DFU who presented to the Outpatient Wound-Care Clinic of the Sorocaba Hospital Complex in São Paulo, Brazil, participated in this study.   Eligibility criteria included 18 years of age or older, diagnosis of type 1 or type 2 diabetes mellitus, presence of DFU, and treatment at the outpatient wound care clinic. Patients with other types of ulcers, hospitalized patients, and individuals who were not physically or mentally able to complete the questionnaire, were excluded from the study.   Sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI), which is a questionnaire designed to measure the subjective sleep quality and sleep disturbances.¹⁸ In the validation of the original instrument, a global PSQI score > 5 yielded a diagnostic sensitivity of 89.6% and specificity of 86.5% in distinguishing good sleepers and poor sleepers,¹⁹ and for the translated and validated Brazilian Portuguese version of the instrument, a sensitivity of 80% and specificity of 68.8% were found.²⁰ The Brazilian Portuguese version of the PSQI consists of 20 items, of which 4 (items 1 to 4) are presented as open-ended questions, 12 (items 5 to 16) are Likert scale questions, and 4 (items 5 to 20) are fixed-choice questions. The items are grouped into 7 components: subjective sleep quality, sleep latency, sleep duration, sleep efficiency, sleep disturbance, use of sleep medications, and daytime dysfunction. Each component is scored from 0 to 3, yielding a global PSQI score between 0 and 21, with higher scores indicating lower quality of sleep. A global PSQI score > 5 indicates an individual is a poor sleeper.^18-20 The interviews took place in a private room to ensure comfort and tranquility to the participants.   The chi-square test, Student’s t test, nonparametric Mann-Whitney U test, and Kruskal-Wallis test were used in the statistical analysis. Statistical significance was set at P < 0.05 for all tests.

Results

  Sixty patients with DFU, ranging in age from 34 years to 71 years, were included in the study. The majority of the patients were women (55%), white (63.3%), and married (33%), as shown in Table 1.   Table 2 shows that 33 (55%) patients had type 2 diabetes 37 (61.7%) had arterial hypertension, 41 (68.3%) had heart disease, 48 (80%) had nocturia, and 41 (68.3%) had diabetes-related eye problems.   The data also shows that 17 (28.30%) patients with DFU reported global PSQI scores ≤ 5, indicating good sleep quality, while 43 (71.70%) patients reported scores > 5, indicating poor sleep quality (Table 3).   With regard to sleeping habits, the majority of study participants 40 (66.7%) reported going to sleep between 9:00 pm and 11:00 pm, getting up between 4:00 am and 5:00 am, and getting 4 to 5 hours of sleep per night. Of all the participants, 25 (41.70%) took between 16 minutes and 30 minutes to fall asleep (Table 4).   It can be observed in Table 5 that 20 (33.3%) patients with DFU also reported taking more than 30 minutes to fall asleep; 30 (50%) reported getting up in the middle of the night or early in the morning; and 35 (58.3%) reported getting up during the night to use the bathroom. In addition, 28 (46.7%) had bad dreams or nightmares, and took medicines to sleep. Data in Table 6 show that 40 (66.7%) patients considered sleep a necessity, 43 (71.7%) took intentional daytime naps, and 35 (58.30%) reported a need for daytime naps.

Discussion

  Patients with DFU, especially those who have difficulty in controlling their feeding regime and blood glucose level, have impaired wound healing, resulting in reduced quality of life.^9,10 Diabetic foot ulcers are usually painful and reduce the mobility and autonomy of patients, interfering with their professional life and resulting in social isolation and low self-esteem; all these factors combined may contribute to poor sleep quality.^9,21   In the present study, patients with DFU were assessed with the PSQI and reported poor sleep quality. Impaired sleep may lead to metabolic dysfunctions because sleep deprivation affects the release of hormones essential for the proper functioning of the body.²² Besides hormonal changes, irregular sleep patterns may result in irritability, reduced ability to plan and perform tasks, mood changes, difficulty concentrating, and changes in the immune system in the short term, and in early aging and cardiovascular diseases in the long term.^20,22,23 Boudjeltia et al²³ detected changes in immune and inflammatory blood markers of cardiovascular disease caused by chronic sleep deprivation and recovery periods in healthy young men.   While studying obstructive sleep apnea, which is prevalent in patients with diabetes, Patt et al²⁴ concluded that oxidative stress and inflammation caused by hypoxia are critical factors in wound healing. Impaired perfusion results in reduced delivery of oxygen and nutrients to the wound site and may delay healing in patients with foot ulcers. Sleep deprivation affects the immune system and is considered a stressor that induces cortisol release in humans or corticosterone (glucocorticoids) release in rodents. Glucocorticoids have, in turn, an immunosuppressive effect. Some studies have identified increased levels of hypothalamic-pituitary-adrenal activity as an important mediator of immune changes in patients with insomnia and sleep deprivation.^22,23,25 Patients with DFU experiencing sleep deprivation, painful physical symptoms, changes in the immune system, and stress may show impaired wound healing. Studies on sleep deprivation have indicated that differences in the inflammatory response and responses of cardiovascular risk markers may be related to sex and age of patients, and that partial night sleep deprivation may lead to an increase in leukocyte, monocyte, and neutrophil counts, total cholesterol, and low-density lipoprotein (LDL) cholesterol.²⁶   In the study sample, 33 (55%) of the patients were women, of which 21 (63.6%) had poor sleep quality; 27 (45%) were men, of which 22 (81.5%) had poor sleep quality. The authors also observed that of the 29 (48.3%) patients 60 years or older, 22 (75.9%) reported sleep disturbances. Thirty-one (51.7%) of the patients were younger than 60 years of age, of which 21 (67.7%) reported sleep disturbances. Thirty-three (55%) patients were women, of which 21 (63.6%) had poor sleep quality. These results are in agreement with the literature.^9,14,18 Studies have shown that the proportion of patients with diabetes is significantly higher among the elderly when compared to younger populations.^8,9,27,28   In the present study, it was also observed that 40 (66.7%) patients who did not have a spouse or domestic partner reported poor sleep quality, possibly indicating that marital status is a variable that may affect sleep quality (ie, presence or absence of a partner may be directly associated with sleep disturbances). Patients without a partner may have feelings of fear, which may influence the sleep pattern. Bed partners are also be able to provide important information about the patient’s sleep pattern.²⁸   Diabetes mellitus is a serious health problem for adults and, when uncontrolled, represents a risk factor for comorbidities that may reduce life expectancy.²⁸ Of the patients who reported poor sleep quality, 22 (81.5%) had type 2 diabetes, 24 (64.9%) had arterial hypertension, 32 (78%) had a heart disease, 34 (70.0%) had nocturia, and 31 (75.6%) had diabetes-related eye problems. In patients with type 2 diabetes, sleep may be interrupted by nocturia, which compromises sleep quality. Day sleepiness may be one of the signs of changes in sleep quality.¹⁴ During sleep, the retinal circulation in patients with diabetes is compromised by hypoxia induced by darkness, which can cause an increase in symptoms of retinopathy.²⁹ High arterial hypertension and diabetes mellitus are the major risk factors for cardiovascular disease mortality.¹⁴   In this study, most patients with poor sleep quality also reported early-morning awakening (50%), and patients who had nightmares or bad dreams reported the need to get up to use the bathroom (66.6%). Bad dreams or nightmares are common problems related to psychological factors, such as anxiety and stress. In stress situations, there is hypersecretion of cortisol, which is associated with insulin resistance.²⁰   With regard to the PSQI items 17 to 20 (Table 6), 43 (71.70%) patients took intentional daytime naps and 35 (58.30%) patients reported a need for daytime naps. Daytime naps may be associated with sleep interruption at night, which contributes to poor sleep quality. Currently, nap episodes and sleep interruptions at night are considered to be part of the natural sleep-wake cycle, but this is a controversial issue. An experimental study showed that sleep deprivation can trigger insulin resistance. Sleep disturbances are commonly comorbid with diabetes mellitus, indicating that diabetes can be either the cause or the consequence of sleep disturbances.¹¹   Most of the participants got between 4 hours and 5 hours of sleep per night and took 16 minutes to 30 minutes to fall asleep. It is recommended that adults need 7 hours of sleep per night, but sleep duration usually decreases with age. It is important to note that the number of hours of sleep needed varies among individuals and a given person can feel rested after a short period of time.³⁰ When the PSQI component scores and global PSQI scores were evaluated together, the relationship between them became more clear. For example, an individual who reported getting less than 5 hours of sleep per night (PSQI item 4), and taking more than 30 minutes to fall asleep (PSQI item 2), has poor sleep quality (global PSQI score > 5) and, consequently, can be sleepy during the day (PSQI item 17), and feel the need for daytime naps.   In order to assess sleep quality, the sleep pattern of patients should be determined. For this, health professionals should investigate the patients’ daily routine and ask the patients to record the time they go to sleep, how long they take to fall asleep, sleep duration, the number of times they get up at night, how long they take to fall asleep again, and at what time they get up in the morning.¹⁸   Intervention actions indicated to promote a healthy sleep habit in patients with DFU include: maintaining a regular sleep schedule (bedtime and rise time) even on weekends; going to bed only when sleepy; getting out of bed if unable to fall asleep within 15 to 20 minutes and going to another room; performing nonstimulating activities until feeling sleepy; avoiding more sleep than necessary; avoiding stimulating physical activities within 4-6 hours of bedtime; having a light snack before bed; avoiding heavy meals; lowering the lights; reducing room noise; avoiding stimulants, such as nicotine and caffeine (eg, chocolates, coffee, soft drinks) 4-6 hours before bedtime; avoiding alcohol, because it can disrupt sleep; and avoiding daytime naps, or limiting naps to 20 minutes, and not napping after 3:00 pm.^18,31-33   The assessment of quality of life, self-esteem, self-image, and sleep quality in patients with DFU allows the identification of important aspects that should be taken into account in the planning of the physical, mental and social rehabilitation of these patients. Therefore, the authors believe that this study will help health professionals in the planning and implementation of actions to improve the quality of life of patients with DFU.   Further studies with a larger number of patients are necessary to obtain a better understanding of the aspects related to the quality of life of patients with diabetes mellitus.

Conclusion

  Patients with DFU have poor sleep quality. Sleep disturbances have a major health and socioeconomic impact, especially when associated with chronic diseases, such as diabetes mellitus, hypertension, cardiovascular diseases, and chonic venous insufficiency. In a previous study, the authors evaluated sleep quality in 100 patients with venous leg ulcers using the PSQI,¹⁵ as part of a broader study to assess sleep quality in patients with ulcers in the lower extremities. It was observed that 64% of patients with venous leg ulcers had poor sleep quality.¹⁵ However, DFU and venous leg ulcers have different causes and different associated factors. Sleep quality in patients with DFU may be affected by factors such as poor glycemic control, nocturnal hypoglycemia, and nocturia, which may not affect patients with venous leg ulcers.^16,17 Therefore, sleep quality should be investigated separately in these 2 patient populations.   This study reaffirms the need to redirect the focus of the treatment of patients with DFU provided by health care services, such as hospitals, outpatient clinics, and home care, to identify sleep disturbances and changes in the sleep pattern of these patients. It is also important to determine the major health care needs of this population and evaluate the knowledge of the caregiver to deal with the patients’ disabilities.

References

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Address correspondence to: Geraldo Magela Salomé, ET, RN, PhD Av- Francisco de Paula Quintaninha Ribeiro, 280, apt-134, Jabaquara CEP 04330-020 São Paulo, SP, Brazil salomereiki@yahoo.com.br