SUMMARY

Recent years have seem increasing attention to the role of sleepiness in accidents, and especially sleep-disordered breathing as a cause of excessive daytime sleepiness. Impairment in driving skills and increased risk of accidents have been related to OSA. Surprisingly, little data exists to show the effect of CPAP on these problems; this is the first to evaluate its effects on accidents in a prospective manner (following patients forward in time for one year). The authors note their inability to include an untreated apneic control group due to ethical problems of leaving the disorder untreated. The study took place at 59 centers connected with the French homecare network. All subjects were patients referred to a sleep center for symptoms of OSA, for whom this disorder was diagnosed with either all-night polysomnography or respiratory polygraphy. Polysomnography was used in all cases who later underwent CPAP titration. Potential subjects included 1,273 patients evaluated over a nine-month period in 1994. Apnea/Hypopnea Indices for patients who had full polysomnography averaged 52.2 (SD=+/-28.1). CPAP was recommended to 973 patients, of whom 893 accepted this and participation in the study. The study consisted primarily in a questionnaire to be completed by each patient just before treatment and after 3, 6, and 12 months of CPAP treatment. Time counters of CPAP machines were also monnitored. The questionnaires inquired whether patients had an accident, of what type, and whether the accident was related to lack of vigilance, fatigue or sleepiness. They were asked whether the accident had resulted in hospitalization and if so, for how long. They were also asked about near-miss accidents. As in the Epworth Sleepiness Scale, they were asked how sleepy they would get in various activities. Of the original group of 893 who started the study, 547 completed all questionnaires. Patients left the study due, most often, to treatment interruption. For comparison, there was a group of 380 patients who received other treatment or refused treatment. At the beginning of treatment, 60 patients reported having real accidents and 151 reported near-misses in the previous year. About half of the real accidents and three-quarters of the near-misses involved automobiles. Domestic real accidents occurred in one-quarter, work accidents in 13%. About half the real accidents and all the near-misses were attributed to impaired vigilance. During the untreated year, 16 patients required hospitalizations for their accidents, totalling 885 days. Once they started treatment with CPAP, the risk of both real accidents and near-misses decreased significantly. Only half the number of real accidents and one-fifth the number of near-misses were reported during the year of treatment. Only eight patients required hospitalization, for a total of 84 days. Those on CPAP who had accidents did not have lower compliance as measured by the machine timers, but did have treater sleepiness on the self-completion scale. In fact, the patients who had real accidents had higher sleepiness scores. The authors describe the decrease in accidents with CPAP as “dramatic.“ This included not only auto accidents but accidents at home and at work. They acknowledged limiting factors to be (a) dependency on self-completion questionnairs alone for accident data; and (b) the absence of a placebo-treated control group. It is possible that patients became more cautious just from interactions with clinicians and researchers emphasizing the role of sleepiness in accidents. They considered it problematic to attempt comparison of their patients with general population data on accidents because of the older age range of their patients. With these reservations, they reported that their patients seemed to have higher accident rates than the general population rates before treatment, and lower rates than the general population during treatment.

COMMENTS

This is reassuring news, that CPAP, already well proven effective as a treatment for obstructive sleep apnea, is also effective for one of the more alarming complications or hazards of the disease. It is alarming not only because it endangers both patients, their families, or completely unrelated strangers, but because it threatens the driving licenses of apnea patients who go untreated for whatever reason. But beware that a closer look may well show an interval of time, before the identified sleep apnea patient is stabilized on CPAP, when the symptoms continue, the increased risk persists, and the possibility of driving restrictions may even prove warranted. This may amount to a few or even several months, if response of sleep clinics and home care therapists is slow, or patients stop complying. Then it may be useful to have a temporary means of reducing symptoms, such as the new alerting drug modafinil, soon to be marketed in this country. Stand these results “on their head” in terms of time, and they also imply the heightened risk of accidents in the untreated apneic patient. The fact that these accidents involve the workplace may create additional difficulties for the patient still struggling to recover but bearing the stigma of a hazardous disease. Consider also one qualification the authors don’t mention as a problem with their questionnaire data: that, as it dawns on them that they may have a condition identifying them as unsafe drivers, may start to cover up the occurrence of accidents. Some more objective data, such as from police accident records, or medical records, seems important. From my own efforts to gauge accident frequencies in a group of veterans who used CPAP, it seemed obvious that there was considerable reserve about acknowledgement of accidents due to symptoms or unsafe driving. There is (as yet) no test for currrent level of alertness in sleep-disordered patients, like a breath or blood alcohol level to attest to the intoxication of the alcoholic driver. The next, much less best thing for authorities to turn to may be the results of a recent polysomnogram–-or the notes in a doctor’s chart.





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