6.1 Introduction

The consequences of OSAHS vary from annoying to life threatening and include excessive daytime sleepiness, (eg falling asleep at work or when on the telephone or whilst driving), depression, irritability, marital disharmony, sexual dysfunction and learning and memory difficulties.

6.2 Driver and vehicle licensing agency (DVLA) recommendations

Untreated sleep apnoea often causes sleepiness which is dangerous whilst driving and can lead to an increased likelihood of having an accident. Patients should be informed that they must not drive if they feel sleepy, even if the diagnosis of OSAHS is only suspected, and that falling asleep at the wheel is a criminal offence and can potentially lead to a prison sentence. When a person is diagnosed as suffering from sleep apnoea they must be told verbally and in writing that they should inform the Driver and Vehicle Licensing Agency (DVLA) of the diagnosis. This information must also be given to the GP. There should be no problem about keeping a licence provided that patients comply with an effective treatment regimen.

After diagnosis the patient should also inform their insurance company.

The DVLA recommends:¹⁵⁴

Group 1 Licences (normal car licence)

Driving must cease if continuing to cause excessive awake time sleepiness. Driving will be permitted when satisfactory control of symptoms achieved.

Group 2 Licences (HGV, PSV)

Driving must cease if continuing to cause excessive awake time sleepiness. Driving will be permitted when satisfactory control of symptoms achieved and confirmed by specialist opinion.

6.3 The effect of CPAP on driving

The relationship between OSAHS, excessive daytime sleepiness and road traffic accidents has been shown in driving simulator tests and in accident surveys.^{75, 155} Epidemiological studies have suggested a particularly high prevalence of OSAHS in truck drivers.^{156, 157}

Sleepiness is estimated to cause 20% of accidents on motorways, and is associated with both increased rates and severity of accidents.¹¹ A systematic review has documented a substantial base of case-control and cohort studies suggesting that driving performance is impaired, and accident rates increase with sleepiness and OSAHS.⁸⁸ Evidence level 2++,3

Meta-analyses of daytime function identify no RCTs of treatment which affect real-world accident rates.^{73, 83} Future placebo-controlled RCTs of this outcome are not anticipated, not least because of ethical considerations. Laboratory studies of objective driving simulator performance offer surrogate evidence for this area.

A recent sham-controlled RCT in patients with severe OSAHS has demonstrated cross-validating improvements in both sleepiness and driving simulator performance following CPAP.⁷⁵ Active CPAP treatment produced significant improvement in steering accuracy, maintenance of performance over time and reaction times.¹⁵⁸ Evidence level 1+,2+

Attention-biased cognitive performance tests (SteerClear, Trailmaking B, PASAT, Digit symbol) may represent a further surrogate measure relevant to driving. While none have the face validity of a driving simulator, scores are thought to measure performance skills common to real-world driving, including response speed and accuracy, vigilance and visuomotor coordination. In one systematic review, results from the extended vigilance task SteerClear showed no significant improvement following treatment with CPAP in patients with mild OSAHS, although a significant improvement in a single study in patients with severe OSAHS (-6 errors, CI -13 to –1).⁷³ The visuomotor trailmaking B time test did not distinguish individual improvement in the three studies of CPAP treatment for patients with mild OSAHS or the single study for patients with severe OSAHS, but a significant improvement (-4 secs, CI -8 to –1) in a pooled analysis of all four studies. Digit symbol substitution (short-term coding speed) was unchanged by CPAP in mild, severe or pooled RCT patients. Rapid mental arithmetic (PASAT) was improved by CPAP within two mild trials, one severe trial and a pooled analysis (+2 sums, CI 1 to 3).⁷³ Evidence level 1+

CPAP should be considered for the improvement of driving ability in patients with severe OSAHS as it reduces daytime sleepiness.

CPAP treatment should be prioritised to sleepy drivers and occupational drivers with OSAHS given the public health consequences of untreated OSAHS, sleepiness and accidents.

6.4 Effects of CPAP on quality of life

Other consequences of sleepiness may impact on patients’ functional level across a range of work, home and social environments. These have been assessed using a variety of instruments.^{83, 73}

6.4.1 OSAHS-SPECIFIC SYMPTOM SCALES

One systematic review of RCTs of treatment with CPAP reports significant improvements in symptom scores in polysomnographically mild and severe samples.⁷³ The varying symptom scales had broadly overlapping, OSAHS-specific content, covering common nocturnal and daytime symptoms. While significant score improvements were found across all three trials of mild OSAHS and both of the trials of severe OSAHS, p-values were lower in the more severe samples (p<0.001). Evidence level 1++

6.4.2 GENERIC WELL-BEING SCALES

Assorted generic scales (NHP, SF-36 UMACL) containing energy or vitality subscales (with enhanced disease-specific sensitivity) were used to estimate aspects of subjective function and health status in several RCTs of mild and severe OSAHS.^{85, 86, 89} Energy/vitality scores were highly significantly improved in the pooled analysis of all studies (p<0.0001). After clustering by polysomnographic severity, studies indicated that patients with severe OSAHS showed individually significant effects from CPAP.^{89, 104} However, two RCTs in patients with mild OSAHS showed no individually significant improvement in energy/vitality scores.^{34, 86} Quality of life scales with no dimension measuring sleepiness or fatigue (eg the EuroQol) fail to demonstrate any response to CPAP.⁷⁴ Evidence level 1+

Another area of harm associated with OSAHS, and with chronic disease generally, is impairment to psychological well-being. In meta-analysis, combined Hospital Anxiety and Depression Scores (HADS) and Beck Depression Inventory scores were highly significantly improved overall, across four RCTs of mild and severe OSAHS following treatment.⁷³ There was heterogeneity, with one of three trials of mild OSAHS showing no significant improvement in depression rating following CPAP therapy. Meta-analysis of HADS anxiety scores (3 trials) showed no benefit from CPAP either individually or by pooling the RCTs. The least disease-specific outcome included in the meta-analysis was the general health subscore from the SF-36, reported in two RCTs of mild OSAHS and one RCT of severe OSAHS. Although the pooled meta-analysis found an overall improvement in SF-36 well-being scores following CPAP therapy, individual significance was observed only in the single trial involving patients with severe OSAHS. Evidence level 1++

An additional outcome relevant to quality of life was treatment preference in placebo-controlled RCTs of CPAP. The Cochrane analysis reported pooled significant preference for CPAP over an oral placebo for two studies of mild and mixed-severity samples (OR 0.4, 0.2 to 0.8).⁸³ A later meta-analysis of treatment preference sampled an overlapping set of three RCTs, in patients with mild OSAHS. These pooled studies showed no significant preference for CPAP (95%CI 40-65%).⁷³ Evidence level 1+,1++

6.5 The effect of intra-oral devices on sleepiness, driving and quality of life

Uncontrolled improvements in subjective sleepiness scores (baseline vs. IOD) are frequently reported across studies. Ratings relevant to driving (sleepiness while driving) and functional status (work performance, interference with daily tasks) also improve following treatment with an IOD.^{117, 118, 119} Evidence level 1+

6.6 The effect of surgery on sleepiness, driving and quality of life

The most widely assessed surgical procedure (UPPP) did not appear to produce reliable, long term clinical benefits, and daytime outcomes were scarce and unvalidated. Other surgical techniques may show greater promise, but good quality evidence of benefit is lacking.¹³²

Further and more robust evidence for specific surgical techniques is required, and clinical recommendations for surgical treatment for OSAHS cannot be made until this is achieved.

Pharyngeal surgery for OSAHS has no proven benefit and should only be undertaken as part of a randomised controlled trial.