Safety and effectiveness of nurse telephone consultation in out of hours primary care: randomised controlled trial ================================================================================================================== * Val Lattimer * Steve George * Felicity Thompson * Eileen Thomas * Mark Mullee * Joanne Turnbull * Helen Smith * Michael Moore * Hugh Bond * Alan Glasper ## Abstract **Objective** To determine the safety and effectiveness of nurse telephone consultation in out of hours primary care by investigating adverse events and the management of calls. **Design** Block randomised controlled trial over a year of 156 matched pairs of days and weekends in 26 blocks. One of each matched pair was randomised to receive the intervention. **Setting** One 55 member general practice cooperative serving 97 000 registered patients in Wiltshire. **Subjects** All patients contacting the out of hours service or about whom contact was made during specified times over the trial year. **Intervention** A nurse telephone consultation service integrated within a general practice cooperative. The out of hours period was 615 pm to 1115 pm from Monday to Friday, 1100 am to 1115 pm on Saturday, and 800 am to 1115 pm on Sunday. Experienced and specially trained nurses received, assessed, and managed calls from patients or their carers. Management options included telephone advice; referral to the general practitioner on duty (for telephone advice, an appointment at a primary care centre, or a home visit); referral to the emergency service or advice to attend accident and emergency. Calls were managed with the help of decision support software. **Main outcome measures** Deaths within seven days of a contact with the out of hours service; emergency hospital admissions within 24 hours and within three days of contact; attendance at accident and emergency within three days of a contact; number and management of calls in each arm of the trial. **Results** 14 492 calls were received during the specified times in the trial year (7308 in the control arm and 7184 in the intervention arm) concerning 10 134 patients (10.4% of the registered population). There were no substantial differences in the age and sex of patients in the intervention and control groups, though male patients were underrepresented overall. Reasons for calling the service were consistent with previous studies. Nurses managed 49.8% of calls during intervention periods without referral to a general practitioner. A 69% reduction in telephone advice from a general practitioner, together with a 38% reduction in patient attendance at primary care centres and a 23% reduction in home visits was observed during intervention periods. Statistical equivalence was observed in the number of deaths within seven days, in the number of emergency hospital admissions, and in the number of attendances at accident and emergency departments. **Conclusions** Nurse telephone consultation produced substantial changes in call management, reducing overall workload of general practitioners by 50% while allowing callers faster access to health information and advice. It was not associated with an increase in the number of adverse events. This model of out of hours primary care is safe and effective. #### Key messages * Telephone consultation is becoming an increasingly accepted approach to patient care and improves public access to medical information and advice * This study found that nurse telephone consultation halved the number of cases dealt with by general practitioners and was at least as safe as existing out of hours services * Nurse telephone consultation not only replaced telephone advice given by a doctor but led to reductions in both home visits and surgery attendances out of hours * Further testing is required of variants to the system used in this trial, including the selection and training of nurses and the decision support software used * There are clear opportunities for and potential benefits from integrating existing out of hours services with NHS Direct ## Introduction Increasing demands for out of hours care during the past two decades have placed the system of 24 hour care of patients by general practitioners under considerable strain. 1 2 Recent developments in the delivery of primary medical care include the setting up of cooperatives of general practitioners and primary care emergency centres, which reduce the number of hours a general practitioner spends on call or facilitate arrangements for seeing patients. Other options include giving advice to patients over the telephone. Marsh reported in 1987 that 59% of all calls outside normal working hours to two general practitioners over a year could be managed by telephone advice alone, and a recent study in Denmark showed that the introduction of a dedicated telephone service run by general practitioners doubled the proportion of calls that were handled by telephone advice. 3 4 None of these interventions, however, reduces the overall workload in terms of patient consultations. The number of patients managed remains the same across the totality of general practitioners. One could wonder why the care of patients after surgery hours has remained primarily the responsibility of general practitioners when care during the daytime is covered by a primary healthcare team. During nurse telephone consultation experienced and specially trained nurses receive, assess, and manage incoming calls to general practices after surgery hours. 5 This term is preferred to nurse telephone triage as it indicates that the call management options include the provision of information and advice with reference to agreed guidelines, as well as referral to the general practitioner on call and direct contact with the ambulance service. In Canada, the United States, and Scandinavia a range of nurse telephone consultation services has been established. 6–8 In the United Kingdom a new advice and information service, NHS Direct, was announced in the recent white paper *A New NHS*. 9 It will exceed the expectations of a service designed to manage emergency calls outlined in the chief medical officer's report of 1997 10 in providing clinical advice, general information, and referral to other NHS services. Three pilot lines for NHS Direct started in March 1998, and England is to be covered by 2000. North American and British literature on the safety and effectiveness of telephone consultation is limited. Some studies point to the inadequacy of observed telephone encounters between health professionals and callers and highlight the potential for missed cases, 11–18 while others report more favourably. 19 20 Our survey of general practitioners in 1996 showed that not all were convinced of the safety of nurse telephone consultation, although the idea was acceptable to most.21 The main concern, again, was the risk of “missed cases.” The effectiveness and safety of nurse telephone consultation in primary care had yet to be established in the United Kingdom. To address this issue a randomised controlled trial was required, and as a precursor to such a trial we undertook a pilot study for six weeks to establish the feasibility and acceptability of such a service to patients.22 During this study we established that most calls were to be expected during the evening. The full trial started on 23 January 1997 at 615 pm and ended on 20 January 1998 at 1115 pm. A night telephone consultation service was run for a month during the trial and is being analysed separately. We report the overall safety of nurse telephone consultation during the trial and its effects on general practitioners' and hospitals' workload. ## Methods> ### Setting We provided an out of hours telephone consultation service run by nurses for a general practice cooperative in Wiltshire of 55 general practitioners (19 practices) with a combined practice population of 97 000 patients, or roughly the optimum size for a new primary care group. The geographical area covered is about 290 km2. It includes the city of Salisbury but is otherwise predominantly rural. The setting was chosen not only because of the enthusiasm of local general practitioners to take part in the trial but because its geography means that most patients attend a single accident and emergency department and are admitted as emergencies to one hospital, Odstock Hospital in Salisbury, making the monitoring of attendances and admissions comparatively straightforward. The out of hours period was defined as 615 pm to 1115 pm from Monday to Friday, 1100 am to 1115 pm on Saturday, and 800 am to 1115 pm on Sunday. ### Objectives The objective of many trials is to show that one treatment is significantly better than another, but the objective of some trials is to show that two treatments are equally effective.23 The principal objective of this trial, and that used in determining its power, was to establish whether there was equivalence in the number of adverse events generated by a general practice cooperative augmented by nurse consultation compared with a standard cooperative service. A secondary objective was to collect data on the management of calls and on emergency hospital admissions and attendances at accident and emergency departments among those who had contacted the out of hours service. ### Sample size We had few data on adverse events arising from general practice consultations from which to estimate sample sizes. To date, the seminal study on the incidence of adverse events is the Harvard medical practice study.24 In this study 30 000 randomly selected case records of inpatients admitted to acute hospitals were reviewed to develop population estimates of iatrogenic injuries according to the age and sex of the patient and the specialty of the doctor. Adverse events occurred in 3.7% of admissions. This study, however, was of hospital patients and took place in a different healthcare system. James and Pyrgos found an error rate of 3.6% when nurse practitioners in a British accident and emergency department were compared with middle grade doctors, although this was principally the result of overinvestigation.25 If a rate of 3.7% were to be replicated in primary care outside normal working hours 37 calls per 1000 would result in some kind of adverse event. Anecdotally, this seems to be a high estimate, and a study based on this proportion of adverse events would likely be underpowered to establish equivalence in British primary care. Clearly, the worst kind of adverse event is death, and we therefore used death as the basis of our calculation of sample size. For the purposes of this trial we did not try to distinguish preventable deaths from other deaths but studied total deaths among those who contacted either arm of the study during the trial year. During one calendar year around 110 deaths per 10 000 population can be expected in England and Wales.26 Hallam reports values ranging from 130 to 175 out of hours contacts per 1000 population per year.1 Taking into account the facts that there will be a range of numbers of contacts per person from one to many and that we would be dealing only with the evening portion of the out of hours period, we estimated that the service would be contacted by around 10% of the population over a year. Applying these two figures to a population of 97 000 people, we calculated an expected number of deaths within the population contacting the out of hours service to be 107. The death rate might be increased among those contacting out of hours medical services, but the figure quoted is likely to give a more conservative estimate—that is, to produce a larger sample size. To establish exact equivalence is impossible without an infinitely large trial, so limits need to be defined within which equivalence is assumed. We used limits of equivalence from 80% to 125% of the expected number of deaths in the control arm, the usual limits applied in trials of bioequivalence (M J Campbell, personal communication). The expected number in the control arm, assuming deaths to be distributed equally, is about half the total expected, or around 54. Specifying α=0.1 (0.05 in a one sided calculation) and β=0.2, we calculated that 5455 patients would be required in each arm of the trial using the formula described by Jones et al.27 A one sided calculation was used as we were interested to establish only whether the nurse intervention produced worse results (higher numbers of adverse events) than the existing service. Using Hallam's figures again for expected numbers of calls we therefore could reasonably expect that we would achieve the desired sample size within a trial period of one year.1 ### Randomisation The trial year was divided into 26 blocks of two weeks. Within each block, one of each pair of matching out of hours periods—for example, Tuesday evenings—was randomly allocated to receive the intervention, the other being allocated to the normal service, by means of a random number generator on a Hewlett Packard 21S pocket calculator. For logistical reasons weekends (Saturdays and Sundays) were treated as single units for randomisation. The complete pattern of intervention periods was known in advance only to the lead investigators and the trial coordinator (SG, VL, and FT). Nurses providing the intervention knew their shifts only after the duty roster for general practitioners providing out of hours care had been fixed. General practitioners were therefore blind to the intervention at the point at which they were able to choose or swap duty periods. Most were not aware until the start of a period of duty whether nurses were present. The pattern of intervention and control days was not publicised and would have only become apparent to a member of the public on a particular day on calling the out of hours service and discovering whether nurse consultation was operating. ### Intervention Six experienced nurses were recruited in late 1996 and participated in a training programme in the skills required for telephone consultation for six weeks before the trial started. During intervention periods all incoming calls to the cooperative were received by a receptionist, who took patient details, and were then diverted to one of two nurses on duty. The nurse then undertook a systematic assessment of the caller's problem and recommended an appropriate course of action, including management with nurse advice alone, contact with the general practitioner (by telephone, at the surgery, or at home), or direct contact with ambulance services. The nurse was aided by TAS (telephone advice system), a computer based primary care call management system.28 Confidential records were maintained on computer for each call. Calls about children under 1 year old and second calls about a patient on the same day were always referred to a doctor, unless callers had been specifically requested to call back to report progress after being given advice and their condition had improved. Patients and callers wishing to speak directly to a doctor were always able to do so. During control periods the receptionist took patient details and then passed calls on to a doctor. ### Measures of process and outcome Process measures included the age and sex of patients compared with the registered patient population; the most frequent presenting complaints; the date and time of telephone calls; the number of calls handled entirely by nurses; the number of calls handled by a general practitioner; and whether the case was managed by advice, a home visit, or attendance at a surgery or primary care emergency centre. Outcome measures included the numbers of deaths among patients who had contacted the service or for whom the service had been contacted within the preceding seven days, the number of emergency hospital admissions within 24 hours and three days after a call, and the number of attendances at an accident and emergency department within three days after a call. A postal questionnaire was also posted to a sample of around 3000 callers across both arms of the trial. However, we were constrained to conducting a single shot survey—that is, with no second or third rounds of questionnaires—because of concerns locally that the anonymity of patients might be threatened by any system that monitored who had or who had not returned the questionnaire. Our overall response rate, therefore, was low (around 40%), and we have not reported the results in this paper. ### Data and analysis Data on workload were downloaded from the database of calls held by the cooperative and transferred into the statistical package for the social sciences (