Results

One hundred and nineteen patients (88 notified prospectively and 31 identified retrospectively) were enrolled over an 8-month period. Six patients never attended hospital. The average age was 48 (12) years, with 98 males (82%). All patients were general practitioner (GP) referrals, apart from one each from departments of Endocrinology, Dermatology, Health Care of the Elderly, and Nephrology. Approximately half (66/128) of the GP practices in the Nottingham Health District referred patients, with 37 referring one case, 14 referring two cases, 11 referring three cases, three referring four cases, and one referring five cases. Twenty-three per cent (92/394) of GPs referred patients, with 72 referring one case each, 17 referring two cases, and three referring three cases. More than half of patients (72/119, 60%) were referred to a respiratory sleep physician, 45 to an ENT surgeon (38%) and two to a neurologist.

On review at 12 months, patients were subdivided into three main diagnostic categories:

nCPAP group (33 cases): A trial of nCPAP was offered to all patients with a desaturation index (⩾ 4%, per hour) of more than 20 dips/h on overnight oximetry (18 cases), and to those patients with less frequent desaturations but who had excessive daytime somnolence (15 cases), particularly if there was also evidence of obstructed breathing on video. Each nCPAP trial was performed in the sleep laboratory and the mask pressure adjusted until a satisfactory mix of clinical effect and patient comfort was achieved. However, two patients declined a trial and six were unable to tolerate nCPAP.

Surgery group (25 cases): Of those patients seen initially by an ENT surgeon, eight were considered to have significant snoring, not associated with excessive daytime somnolence or apnoeas, and with a surgically amenable upper airway problem. They were deemed surgical candidates without the need for a sleep study. The remaining 17 patients underwent overnight monitoring with no evidence of obstructive sleep apnoea and no significant excessive daytime somnolence.

Simple measures group (37 cases): This group consisted of those patients without frequent desaturation on oximetry or no upper airway obstruction on video, who did not have excessive daytime somnolence and whose snoring was not considered severe enough to warrant surgery. Four patients were seen initially by ENT and not thought to require a sleep study. These case were treated with simple measures alone, eg, weight loss, alcohol avoidance or nasal decongestants.

A further nine cases had alternative diagnoses, two were still awaiting a further specialist's opinion, and seven were lost to follow-up.

REFERRAL LETTERS

Referral letters were available for 111 patients (93%), and the frequency with which each item was mentioned is shown in table 1. The cardinal symptoms of obstructive sleep apnoea are snoring, observed apnoeas and excessive daytime somnolence. However, in 64 patients (58%) the presence or absence of only one of these symptoms was mentioned, with reference to two in a further 40 patients (36%). Information on all three symptoms was available in just seven patients (6%). No significant differences were seen between the major diagnostic categories. Importantly, excessive daytime somnolence was mentioned in only 25% of patients on nCPAP, a group where excessive daytime somnolence is almost universally present, and upper airway anatomy was described in only 41% of those considered for surgery.

WAITING TIMES

Waiting times are summarised in table 2. Interspecialty waiting times were longer than for referrals from GPs, and it was during the former that all losses to follow-up occurred (six patients referred from ENT to a respiratory physician and one patient referred from a respiratory physician to ENT). Excluding six patients who never attended, and six lost to follow-up from ENT to a respiratory physician, 95 of the remaining 107 patients had a sleep study (89%). Where appropriate, nCPAP was commenced 18.9 (12.3) weeks after referral receipt, with 25 of 31 patients (81%) agreeing to a trial still using it at 12 months. After 12 months, only half of the patients on the waiting-list for surgery, and 40% of those on the waiting-list for sleep nasendoscopy, had undergone the procedure (table3).

QUESTIONNAIRES

Sixty-six of 82 initial questionnaires (Q₁) were returned (81% response rate, table 4). The ESS differed between diagnostic groups (p=0.018, ANOVA) being higher in the nCPAP group than in the other two groups (p=0.02 for both comparisons, SNK). Groups did not differ for other symptoms, with most patients being habitual snorers, sleeping in a separate room, and snorting/gasping during sleep. The latter two responses were seen in nearly every surgical patient, reflecting the socially disruptive nature of their illness.

A follow-up questionnaire (Q₂) was sent to 64 of the above patients (two had moved without a forwarding address) with 51 returned (80%). Comparing Q₁ and Q₂ for these 51 patients (table 5), a significant reduction in ESS (p=0.016) and a trend towards reduced snoring frequency (p=0.08) were seen in the nCPAP group. Patients reported being somewhat (33%) or significantly improved (47%), with most satisfied (27%) or very satisfied (53%) with their management (figure).

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Figure Patient responses to: (a) any overall change in symptoms over the 12 months from referral, and (b) their perception of how their problem(s) were investigated and treated. Patients are subdivided according to the main diagnostic groups: prescribed nCPAP, awaiting surgery, and treatment by simple measures alone

Only three of the patients undergoing surgery within 12 months of referral returned Q₂, a number too small to draw any valid conclusions. However, 10 patients still awaiting surgery or sleep nasendoscopy responded. One patient reported an overall improvement in symptoms, with no change in eight patients and some worsening in one. Forty-two per cent of patients expressed some dissatisfaction about their management (figure). Similarly, there was no significant change in the simple snorers group (table 5) with most patients reporting no overall change in their symptoms, and 33% dissatisfied with their management (figure).

Discussion

The present study is the first report examining all primary referrals with suspected sleep-disordered breathing within a defined health district. The annual burden on our service extrapolates to 180 referrals, 50 of whom require nCPAP. The study also demonstrates important delays in management of some patients, chiefly those referred between specialties and those awaiting surgery, with many unhappy with the service provided. Good symptom control was seen with nCPAP, and most patients continued to use it at 12 months. Too few patients had surgery to comment on its efficacy, but symptom control in those awaiting surgery, and in those treated by simple methods, was generally unsatisfactory. Referral letters generally had too little information to direct initial management and referral patterns varied, with half of all GP practices not referring patients while some GPs referred up to three.

Most patients on nCPAP have a worthwhile clinical improvement, with a significant reduction in ESS and a trend towards reduced snoring frequency, and most were satisfied with their management (table 5, figure). The observed compliance rate of 81% at 12 months follow-up compares favourably with other studies.8 9 In contrast, there was no overall reduction in ESS, snoring frequency, sleeping in separate rooms and frequency of nocturnal choking in the simple treatment group. Only three of those patients who had surgery by 12 months returned Q₂ (two clinically improved and satisfied, one worse and dissatisfied). Patients still on the waiting list for surgery or sleep nasendoscopy were also advised on simple measures but most had no symptom improvement by 12 months after referral. This group had the greatest dissatisfaction with their management (42%). Responses in the simple treatment and surgery groups could perhaps be improved by increasing the number of patients having nCPAP trials or using other devices considered effective in some patients with snoring or obstructive sleep apnoea, such as a mandibular advancement device.10 However, the clinical efficacy of the latter remains to be shown conclusively.

Presently, the respiratory medicine and ENT departments do not co-ordinate referrals. Thus, many patients with obstructive sleep apnoea may be referred initially to ENT, and then onto a respiratory physician, resulting in more hospital visits, significant delays in investigation and treatment (average of 16 weeks) and loss to follow-up. Improved clinical data, as provided by a standardised referral form or a patient questionnaire relating to a small number of important clinical risk factors,11 would help to determine the appropriate specialist for initial referral. Patients with socially disruptive snoring, no excessive daytime somnolence and a very low probability of obstructive sleep apnoea based on clinical risk factors11 would be sent directly for surgical opinion, while the remainder would be seen initially by a respiratory physician.

This co-ordinated approach should not increase the respiratory service workload significantly, since most patients already undergo sleep studies, but it should greatly reduce the ENT out-patient workload. In the present study, only 29 of 59 patients seen by ENT (45 GP and 14 respiratory physician referrals) had, or were waiting for, surgery or sleep nasendoscopy. Reducing referrals to ENT by 50% could shorten the interval to ENT assessment and, consequently, the waiting time to surgery, while shortening the time to diagnosis by a mean of 4 months in those patients not requiring ENT input.

We feel that the results of the present study are representative of the services provided by most District General Hospitals, but acknowledge that some centres may already have a very close working relationship between respiratory and ENT departments. Nevertheless, the study does highlight a number of issues that will be relevant to most centres. Importantly, it demonstrates the effectiveness of nCPAP in improving symptoms, compared to simple measures.