Am Fam Physician. 2001;63(3):543-544
Excessive daytime sleepiness is a specific indicator of an underlying sleep disorder, the most common of which is obstructive sleep apnea syndrome. Insomnia and sleepiness are two of the clinical criteria required for making a diagnosis of obstructive sleep apnea. This condition is known to affect at least 2 to 4 percent of the general population. However, the actual incidence is likely to be much higher because only a small number of persons diagnosed with sleep apnea complain of excessive daytime sleepiness. Obstructive sleep apnea syndrome is confirmed by the multiple sleep latency test. Chervin hypothesized that underdiagnosis of obstructive sleep apnea occurs because physicians place too much emphasis on daytime sleepiness in the clinical evaluation.
Data were taken from a sample of patients referred for diagnosis of sleep apnea to examine the words patients used to describe their symptoms and assess the extent to which these words may be objectively predicted. Adults referred to a sleep laboratory for full-night polysomnography were enrolled in the study. The patients were diagnosed with obstructive sleep apnea based on the established criteria of an apnea/hypopnea index of 5 or higher. The author also used a seven-item questionnaire that asked specifically about sleepiness, fatigue, tiredness and lack of energy (see the accompanying table).
A total of 190 adults met all inclusion criteria. The mean age of the study participants was 48.6 years, and the study included 117 men and 73 women. The majority of patients rated the frequency with which they suffered from sleepiness, fatigue, tiredness and lack of energy as “occasional” or “often.” Seventy-three percent reported at least one of these symptoms occurring often or almost always. Thirty-seven percent of patients admitted to almost always having at least one of these problems. A lack of energy, fatigue or tiredness was reported to be problematic often or almost always by 62, 61 and 57 percent of patients, respectively. Sleepiness was reported to be a problem by 47 percent. In assessing the most bothersome complaint and the one they wish could be cured, 36 percent of patients stated lack of energy. Only 25 percent said sleepiness was their worst problem.
| Item number | Item topic | Number of unambiguous responses |
|---|---|---|
| 1 | Sleepiness is a problem for me. | 188 |
| 2 | Fatigue is a problem for me. | 188 |
| 3 | Tiredness is a problem for me. | 189 |
| 4 | Lack of energy is a problem for me. | 190 |
| 5 | Which problem most affects your ability to accomplish what you want? | 177 |
| 6 | Which is the worst problem for you? | 172 |
| 7 | If you could be cured completely of only one of these problems, which one would you choose? | 173 |
The multiple sleep latency test results that confirmed the diagnosis of sleep apnea showed no significant correlation with sleepiness, fatigue, tiredness or lack of energy. The Epworth score was significantly associated with lack of energy, tiredness and sleepiness but not fatigue. Women in the study had a greater incidence of having all four complaints.
The author concludes that complaints of fatigue, tiredness and lack of energy appear to be as important as complaints of sleepiness in patients diagnosed with obstructive sleep apnea syndrome. This is especially true for women. Physicians should consider a diagnosis of sleep apnea in patients who complain of fatigue or lack of energy, even if they do not admit to excessive daytime sleepiness.