Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a very common respiratory disorder in industrialized societies, and occurs in 24% of men and 9% of women in middle age.1 It consists of repeated episodes of limited airflow or airflow blockage during sleep causing micro-awakenings and intermittent hypoxemia. It has a serious impact on health,2 causing hypertension3 and cardiovascular disease.4,5

OSAHS patients often present significant cognitive limitations6 and a generally poorer quality of life.7 Obesity and poor quality of rest, which are often seen with this disorder, are associated with mood disorders such as anxiety and depression.8 However, one of the most debilitating symptoms of this syndrome is excessive daytime sleepiness. Tiredness, together with loss of alertness and attention deficit, not only makes it difficult for OSAHS patients to function on a daily basis, but also contributes to a general increase in mortality, due to the increased risk of road traffic accidents.9

Only 5%–9% of patients with OSAHS are diagnosed10 and the burden on public health services in Western societies is considerable.11 Moreover, OSAHS involves indirect costs that are very difficult to calculate, such as limited ability to work, accidents at work, and loss of productivity.12

Some studies have evaluated work performance in patients with OSAHS, but results have been disputed. The syndrome has been shown to have a negative impact on patients’ ability to concentrate, to organize time, to learn new tasks and to carry out monotonous tasks.13,14 Another study found that OSAHS, when associated with excessive daytime sleepiness, was detrimental to work performance.15,16 Despite some methodological limitations, cohort studies have found a higher rate of absenteeism in patients with symptoms of OSAHS.17,18 However, no solid conclusions have been drawn regarding the relationship between OSAHS and absenteeism.19

Some authors have reported a relationship between OSAHS symptoms and increased risk of work-related accidents. In a prospective study, Lindberg et al.20 showed a 2-fold increase in the risk of workplace accidents in patients who snored and who had daytime sleepiness vs patients without those symptoms. Other large population studies,21 including professional drivers22,23 or rural workers,24 found that some OSAHS symptoms, such as snoring, sleep apneas or daytime sleepiness, evaluated by direct questioning or questionnaires, were associated with a greater risk of accidents in the workplace. However, very few studies have evaluated the rate of work-related accidents in patients with a definitive diagnosis of OSAHS.

In view of the lack of consensus between studies investigating productivity and work accidents in patients with OSAHS, we designed a cross-sectional, descriptive ex postfacto study of productivity and work accidents in a sample of OSAHS patients vs a group of non-OSAHS individuals. A sleep study was performed in both the clinical group and the control group using the gold standard test, polysomnography. The study hypothesis was that participants in the clinical group would have a higher rate of work-related accidents and absenteeism than the control group, and that OSAHS patients would have poorer productivity than healthy subjects. This article was written following the Hartley guidelines.25

Data for this study were collected between 2010 and 2012 in 2 sleep units in hospitals in the north and in the south of Spain. The sample comprised 259 individuals who attended the sleep unit and underwent consecutive polysomnography studies. Participants were actively employed or had been unemployed for up to 6 months. All participants signed informed consent; only 6 individuals refused to take part in the study. Of the remaining 253 subjects, 204 were men and 49 were women, with ages ranging from 22 to 65 years, mean 46.85±9.5 years. The clinical group consisted of 182 patients with a diagnosis of OSAHS, and 71 non-OSAHS subjects were included in the control group. Patients with a diagnosis of other sleep disorders, serious debilitating diseases, alcohol or other drug addictions, or who were receiving treatment with neuroleptics, tranquilizers or other medications that could alter sleep or cause excessive daytime sleepiness, were excluded.

The characteristics of the 253 study participants, classified according to diagnosis of OSAHS (n=182; AHI=42.6±28.4) or absence of OSAHS (n=71; AHI=2.1±1.7), are shown in Table 1. The only differences between the OSAHS group and the control group lay in the distribution of sex, BMI and some of the job categories, such as scientific or intellectual professions. The type of working schedule was similar in both study groups. Patients with OSAHS were more frequently hypertensive and had a higher degree of psychological distress than the non-OSAHS control group.

Table 2 shows the characteristics of participants with OSAHS and their assessment of daytime sleepiness and perceived quality of sleep. Patients with OSAHS had more excessive daytime sleepiness than the control group (P=.021), but Pittsburgh scores for poor quality of sleep were similar in both groups (P=.238).

Table 3 compares repercussions in the workplace between the OSAHS group and the control group. Both groups had similar rates of work-related accidents, but it is interesting to observe that patients with OSAHS had a significantly higher rate of absenteeism and poorer productivity.

A logistic regression model was constructed that included at least age, sex, excessive daytime sleepiness, subjective quality of sleep, and OSAHS or control subject. The only variables of interest when evaluating workplace accidents were use of medications, physically stressful work, and social level; the model produced an adjusted R2 of 0.126 (P=.001), and the only variable that showed an independent association with workplace accidents was physically stressful work (OR=0.347; CI: 0.167–0.718; P=.004). With respect to absenteeism, significant variables were: OSAHS or control group subject, and subjective quality of sleep (adjusted R2=0.045; P=.048). Notwithstanding, the only factor with an independent influence on work absenteeism was OSAHS subject (OR=2.718; CI: 1.004–7.356; P=.049). A linear regression model was used for productivity, and the variables accepted by the model were age, subjective quality of sleep, psychological distress, OSAHS or control subject and AHI. The model showed an adjusted R2 of 0.133, F=7.412 (P=.000), and there was an independent association between productivity and a diagnosis of OSAHS (β coefficient=0.251; P=.002) and psychological distress (β coefficient=−0.249; P=.001).

This study found that patients with OSAHS did not have a significantly higher number of work-related accidents, although, compared to the non-OSAHS group, they did have a higher percentage of long-term absenteeism, lower productivity levels, and a high rate of psychological distress. These findings are significant, and confirm that OSAHS is a disease with considerable social and economic repercussions.

The multivariate analysis corroborated the finding that patients with OSAHS had a lower level of productivity. This result was previously reported by Swanson et al.32 who used an OSAHS symptom questionnaire to show that individuals with a high risk of suffering this disease had problems concentrating and organizing themselves at work, in addition to a loss of productivity. Similarly, Grunstein et al.33 reported that sleepiness associated with the risk of sleep-disordered breathing was the main factor in loss of productivity and performance, although the sample was composed of obese individuals who were consequently more likely to present other sleep disorders associated with obesity. Nena et al.34 using the Endicott productivity scale, did not find any relationship with severity of OSAHS or with sleep quality, although it should be borne in mind that their sample contained only patients with OSAHS. Thus, very few studies have investigated productivity in OSAHS patients compared to a control group using standardized questionnaires. Moreover, we found that psychological distress led to poorer productivity in patients with OSAHS. There is very little work on this aspect in the scientific literature.

With regard to days off work due to illness, a greater rate of long-term absenteeism was found in OSAHS patients, in line with the findings of other authors. Sivertsen et al.18 showed that subjects with OSAHS more often took periods of sick leave of longer than 8 weeks; other authors have also suggested that OSAHS is associated with a greater risk of taking sick leave and receiving a disability allowance.17 Various studies have emphasized the importance of sleepiness as a determining factor for work absenteeism,18,32,35 although some of these have limitations. For example, Sivertsen et al.18,35 used the Karolinska sleep questionnaire, but did not perform an objective sleep study; Accattoli et al.13 used only polygraph as their sleep study, and only evaluated work performance on the basis of some questions related to difficulties encountered at work.

The number of work-related accidents in our patients was not significantly higher than in the control group. In line with this study, Karimi et al.36 found similar work-related accident rates in OSAHS patients compared to healthy participants. In another setting, Accattoli et al.13 compared the rate of work-related accidents in healthy workers to those with a diagnosis of OSAHS and found that administrative workers with severe OSAHS had a higher percentage of work-related accidents compared to controls in the same sector, but it must be emphasized that this group in general had a higher occupational accident rate than non-OSAHS workers in other areas. Workers with respiratory disorders were also found to have a greater risk of work-related accidents;37 however subjects were classified on the basis of oximetry, a test that is not recommended for a clear diagnosis of OSAHS.

To conclude, our study was conducted in a large cohort, using rigorous methodology with validated questionnaires for studying work productivity and perceived quality of sleep. Polysomnography was used as the reference test in sleep studies. The most relevant findings are the relationship of OSAHS with low work productivity, increased periods of sick leave lasting longer than 30 days, and a greater degree of psychological distress. These results have a clear application, which should be studied in clinical practices, and demonstrate the involvement of OSAHS in the working life of these patients.

This study was possible thanks to funding from a Teaching and Research Personnel Training Grant from the Regional Government of Andalusia.

The authors declare that they have no conflict of interests.