Service mapping
A copy of the survey questionnaire has been published elsewhere.82 This is an open access article distributed under the Creative Commons Attribution licence 4.0 (CCBY), which permits unrestricted use, distribution and reproduction in any medium, provided that the original work is properly cited. See https://creativecommons.org/licenses/by/4.0. The text and Tables 5 and 6 below include minor additions and formatting changes to the original. Survey responses were obtained from 50 of 53 NHS trusts with a relevant remit (94% response rate). The survey was completed by FOI officers, acute care pathway leads, service directors and lead nurses.
| Theme | PDU characteristic | n/N (%) |
|---|---|---|
| PDU setting | Psychiatric hospital | 6/6 (100) |
| Acute hospital | 1/6 (17)a | |
| Co-located with place of safety (section 136 suite)b | 5/6 (83) | |
| Trust-wide aim of service | Reduce presentations at ED | 4/6 (67) |
| Reduce ED breaches | 3/6 (50) | |
| Reduce inpatient admissions | 3/6 (50) | |
| Reduce out-of-area beds | 1/6 (17) | |
| Improve patient experience | 1/6 (17) | |
| Two or more aims | 5/6 (83) | |
| PDU environment | Overnight stays | 6/6 (100) |
| Recliners rather than beds | 6/6 (100) | |
| Partitioned areas | 6/6 (100) | |
| Maximum hours of stay | 12 hours | 2/6 (33) |
| 23 hours | 1/6 (17) | |
| 2 days | 2/6 (33) | |
| 3 days | 1/6 (17) | |
| Referral/entry to unit | Voluntary admissions only | 6/6 (100) |
| Liaison psychiatry | 6/6 (100) | |
| CRHT team | 5/6 (83) | |
| Street triage | 5/6 (83) | |
| CMHT | 2/6 (33) | |
| GP | 1/6 (17) | |
| Third or voluntary sector services | 1/6 (17) | |
| Police | 1/6 (17) | |
| Self-referral | 0/6 (0) | |
| Self-referral if included in crisis care plan (also known as joint crisis plan), a plan developed between service users and their clinical teams, typically for service users who experience crisis frequently. | 1/6 (17) | |
| Approved mental health professional | 1/6 (17) | |
| Activity on unit | Primarily assessment | 1/6 (17) |
| Primarily therapeutic input | 1/6 (17) | |
| Both assessment and therapeutic input | 4/6 (67) | |
| Capacity and duration of stay | Mean (SD), range (N) | |
| Capacity | 5.6 (1.4), 4–8 (6) | |
| Average LOS on unit (hours) | 25.3 (18.4), 8–48 (6) |
| Role (NHS pay band) | Sites including role in staff team |
|---|---|
| Nurse (band 6), n (%) | 6 (100) |
| Nurse (band 5), n (%) | 1 (17) |
| Healthcare assistant (band 3), n (%) | 4 (67) |
| Healthcare assistant (band 2), n (%) | 1 (17) |
| Administrative support (band 4), n (%) | 3 (50) |
| Administrative support (band 3), n (%) | 1 (17) |
| Psychiatrist; part time, n (%) | 6 (100) |
| Staff on shift; nurses and healthcare assistants: | |
| Day shift, mean (SD), range | 1.7 (0.31), 1–3 |
| Night shift, mean (SD), range | 1.7 (0.31), 1–3 |
| Staff : patient ratio; nurses and healthcare assistants: | |
| Day shift, ratio (SD), range | 1 : 21 (1.2), 1 : 1 to 1 : 4 |
| Night shift, ratio (SD), range | 1 : 2.3 (1.2), 1 : 1 to 1 : 4 |
PDUs were present in a relatively small number of trusts, six (12% of trusts), with a further two planned but yet to open.82 The locations of the trusts that had a PDU were Sheffield, Lincolnshire, Birmingham, Coventry and Warwickshire, South West London and Sussex. Of the PDUs planned, one would be in Nottinghamshire and one serving Rotherham, Doncaster and South Humber. Four decommissioned PDUs were identified – one in Leeds and three in Lancashire. Of the decommissioned PDUs, the unit in Leeds had operated with ward status and so staff had been unable to refer patients onward for inpatient care. This meant a protracted LOS for some in what was designed to be a short-stay unit with communal sleeping areas. Of the Lancashire units, one received an unfavourable quality report due to lengthy patient stays and dissatisfaction with unit layout and sleeping arrangements.89 The Lancashire trust repurposed units as crisis assessment spaces without overnight stays.
All six PDUs were located on the mental health NHS trust site (see Table 5), although one of those was in a shared site by the MHT and the acute hospital. In five of six sites, the PDU was co-located with the trust’s place of safety (Section 136 facility). The majority of units were designed to reduce pressure on EDs, and half were designed to reduce inpatient admissions. Two PDUs had addition aims to reduce out-of-area placements and improve the patient experience. All PDUs facilitated overnight stays, with partitioned areas for sleeping in recliners rather than beds, and had a capacity of four to eight service users. All units only accepted voluntary patients. The majority of PDUs aimed to deliver both assessment and therapeutic input (four of six). All PDUs accepted referrals from liaison psychiatry, with the majority accepting referrals from CRHT teams and street triage (an outreach service run by the police and mental health services). However, substantial heterogeneity of pathways was also identified: referrals from third or voluntary sector services, police, general practitioner, approved mental health professional or self-referral when included in crisis care plan, were each only available at one trust.82
PDUs had a high staff-to-patient ratio. In the day, the mean staff-to-patient ratio for nurses and HCAs combined was 1 : 2.1 [standard deviation (SD = 1.2)], rising at night to a mean of 1 : 2.3 (SD = 1.2). Staffing includes some allocated staff time from psychiatry (see Table 6). Although all units have a high staff-to-patient ratio, a sizeable difference was observed; units ranged from 1 : 1 staffing to 1 : 4 staffing.83
Survey findings indicate that trusts with a PDU were approximately twice as likely than trusts without a PDU to have several crisis services, including crisis houses, crisis cafes or crisis drop-in services and acute day units (see Table 7). About half of trusts have hospital-based assessment services without overnight stays, and this is the same whether a trust has a PDU or not. The percentage of trusts with short-stay assessment wards was similar across trusts which have and do not have a PDU.82
| Components of crisis care pathway | Trusts nationally, n/N (%) | Trusts with PDU, n/N (%) |
|---|---|---|
| PDU | 6/50 (12) | – |
| Community-based assessment servicea | 50/50 (100) | 6/6 (100) |
| Hospital-based assessment service without overnight staysb | 23/50 (46) | 3/6 (50) |
| Street triage servicec | 29/50 (58) | 5/6 (83) |
| Sanctuary/crisis caféd/crisis drop-in service | 18/50 (36) | 4/6 (66) |
| Crisis house(s)e | 17/50 (34) | 4/6 (66) |
| Acute day unit | 7/50 (14) | 2/6 (33) |
| Crisis family placements | 1/50 (2) | 0/6 (0) |
| Short-stay assessment wards | ||
| Triage or short-stay assessment ward | 13/50 (26) | 1/6 (17) |
| Maximum length of stay on triage or short-stay assessment ward | ||
| 1–7 days | 4/13 (31) | – |
| > 7 days | 9/13 (69) | – |
| Number of triage/short-stay assessment wards at trust | ||
| 1 | 7/13 (54) | – |
| 2 | 5/13 (38) | – |
| 3 | 1/13 (8) | – |
| Number of triage/short-stay assessment beds at trust | ||
| < 10 | 3/13 (23) | – |
| 10–19 | 5/13 (38) | – |
| ≥ 20 | 5/13 (38) | – |
Systematic review
Twelve studies were included in the review. Figure 3 depicts the flow of information through the review. Study characteristics and further information regarding units evaluated in included studies can be seen in Table 8 and in Appendix 1, Table 33.
FIGURE 3 Selection of studies for inclusion in systematic review. (Figure not reproduced here; see the original article.)
| Study reference | Service description | Study design and duration | Setting | Participants | Outcomesa | ||
|---|---|---|---|---|---|---|---|
| Intervention | Comparison | N (alternative n/comparison n) | |||||
| Braitberg et al.40 | 24-hour BAU | Pre/post study; 2-year comparison period | Australia, Royal Melbourne Hospital; 72,000 ED presentations per annum | Adults admitted to the BAU; no patients with a medical diagnosis | Adults aged 16+ years ED presentations with LOS 3–24 hours, diagnosis coded as MH issue, psychosocial crisis or related to intoxication | n = 5426 (2379/3047) | ED LOS; time to ED clinician; time to EMH clinician; ED security (‘code grey’) rates; ED restrictive intervention rates |
| Browne et al.91 | 48-hour PAPU | Pre/post study; multiple comparison periods | Australia, Royal Melbourne Hospital | All ED patients; no transfers from other EDs or other psychiatric catchment areas | All ED patients; no transfers from other EDs or other psychiatric catchment areas | Not reported | ED LOSLong waits in ED; ED security (‘code grey’) rates; ED mechanical restraint rates; ED 1 : 1 nursing time; ED 1 : 1 nursing cost |
| Gillig et al.92 | 24-hour extended evaluation unit | Comparison study; 2.5-week (intervention)/4-week comparison period; 30-day follow-up for intervention | Louisville, Ohio (intervention); Cincinnati, Ohio (comparison). Ohio Valley urban area, 600 patient visits per month | Adults aged 18+ years attending the PES | Adults aged 18+ years attending the PES | n = 783 (435/348) | Hospitalisation rates from ED; inpatient admissions (from ED & unit); hypothetical hospitalisations |
| Kealey-Bateman et al.93 | 72-hour joint SSU and Missenden assessment | Comparison study; 18-month (intervention)/unknown comparison period | Royal Prince Alfred Hospital, inner-city Sydney | Patients admitted to the SSU via ED | Patients admitted to a PECC | Not reported | Admission to unit via ED |
| Lester et al.94 | 48-hour CALM service | Pre/post study; 1-year comparison period; 30-day follow-up | USA, Ohio; 72,000 annual ED visits, ~7% for behavioural health complaints | ED patients who received a psychiatric consult | ED patients who received a psychiatric consult | n = 4598 (2387/2211) | ED LOS; hospital LOS; psychiatric hospitalisation rate; admission to unit via ED; discharged from ED; 30-day readmission rate; unit LOS |
| Mok and Walker95 | 3-day SSU | Comparison study; 8-month comparison period | Canada, metro Halifax | Patients admitted to the regular-stay unit | Patients admitted to regular-stay unit | n = not reported (124/not reported) | Ward occupancy rates |
| Parwani et al.37 | 24-hour Psychiatric Observation Unit | Pre/post study; ITS for analysis; 18-month comparison period | North Eastern USA; 1541-bed tertiary care academic medical centre | Adult ED patients aged 17+ years evaluated by the acute psychiatry service. No patients who: left ED, diverted elsewhere, never arrived, or discharged to court/law enforcement | Adult ED patients aged 17+ years evaluated by the acute psychiatry service. No patients who: left ED, diverted elsewhere, never arrived, or discharged to court/law enforcement | n = 7299 (3798/3501) | ED LOS; Crisis Intervention Unit LOS; hospital LOS; psychiatric hold rate; inpatient admission rate |
| Schneider and Ross96 | 3-day crisis unit | Comparison study; 2-year comparison period; 30-day follow-up | USA, Connecticut, community hospital | Patients admitted to the crisis unit | Patients admitted to the inpatient service | n = 1370 (590/780) | Average unit LOS; 30-day readmission rate |
| Spooren et al.97 | Three 72-hour psychiatric crisis units | Pre/post study, case–control design; 6-month (pre)/13-month (post) comparison period; 1-month follow-up | Belgium, three urban hospitals (intervention); University of Ghent (comparison) | ED patients referred every third week to the psychiatric crisis units | ED patients referred every third week for short-term psychiatric inpatient treatment | n = 208 (171/37) | Psychological scales: symptoms; patient reported improvement |
| Stamy et al.80 | EmPATH unit | Pre/post economic evaluation; 2-year comparison period | USA, Midwestern academic ED | All ED patients aged 18+ years | All ED patients aged 18+ years | n = 46,567 (23,231/23,336) | ED revenue; psychiatric boarding time (time waiting for a bed or for transfer); ED LOS; leaving ED without being seen; leaving ED against medical advice or eloped; inpatient admissions; fatalities |
| Tretheway et al.45 | Short-term PDU | Comparison study; 1-year comparison period | UK, Birmingham | All patients referred to the PDU, ED presentations via street triage team and patients admitted to an inpatient unit following assessment by rapid assessment interface and discharge | All ED presentations via street triage team and patients admitted to an inpatient unit following assessment by rapid assessment interface and discharge | n = 980 (385/595) | Inpatient admissions via liaison psychiatry; ED presentations via street triage |
| Van der Sande et al.98 | 4-day special care unit for suicide attempters (SOS-afdeling) | RCT, 12-month follow-up | Netherlands, Utrecht University Hospital | Aged 15+ years and attending for somatic treatment of the consequences of a suicide attempt | Aged 15+ years and attending for somatic treatment of the consequences of a suicide attempt | n = 274 (140/134) | Occurrence of subsequent suicide attempts; medical care received in the year subsequent to index suicide attempt; psychological scales: symptoms; psychological scales: hopelessness |
Narrative synthesis
Study characteristics
In the review, 12 studies were included, of which five studies were from the United States,37,79,91,93,95 three from Australia,40,90,92 and one each from the Netherlands,97 Belgium,96 UK45 and Canada.94 The review comprised four pre/post studies,40,79,90,93 five comparison studies,45,91,92,94,95 one ITS,37 one case–control study96 and one RCT.97
Pre/post studies took ED or psychiatric patients as their population, except for a study where the 2379 intervention participants of 5426 participants in total were from the short-stay behavioural assessment unit.40 Browne et al.90 took ED patients as their population, as did Stamy et al.79 who included 46,567 patients in total in their study sample. Lester et al.,93 used data from 4598 patients in total, all of whom had received a psychiatric consult in the ED.
From the comparison studies, comparison groups comprised 348 patients accessing PESs;91 psychiatric emergency care centres;92 admitted to the regular-stay units;94 780 patients admitted to the inpatient service;95 and 595 ED presentations via street triage teams and patients admitted to an inpatient unit via liaison psychiatry.45
In terms of study outcomes, five studies examined ED LOS,37,40,79,90,93 of which three studies had this as a primary outcome.37,40,93 Four studies had inpatient admissions as an outcome,37,45,91,93 one as a primary outcome.93 Two studies looked at security code events and the use of restrictive interventions, such as mechanical restraint and sedation,40,90 psychometric outcomes,96,97 and 30-day readmission rates.93,95 One study assessed rates of admission to the short-stay unit via the ED.92
Unit characteristics
Units could be designed with multiple purposes in mind. Five units were designed to reduce pressure on ED,37,45,79,90,92 four to provide a more therapeutic environment than the ED,40,45,90,92 three to reduce psychiatric admissions,45,91,94 three to reduce time spent in hospital,95–97 and units to stabilise or improve patient well-being.95–97 In addition, individual units had specific remits: to reduce the risk of future suicide attempts,97 reconnect with outpatient treatment,95 reduce out-of-area transfers,94 and offer crisis-focused psychotherapy and case management services.93 Refer to Table 2 for more information regarding individual units.
Admission criteria were variable. Units accepted patients with mental health problems or who required psychiatric care (n = 4),40,90,92,93 who were likely to be discharged within a short time frame or benefit from short-term admission (n = 4),37,40,92,94 under the influence of drugs or alcohol (n = 2),40,92 experiencing an acute behavioural disturbance (n = 1),40 experiencing acute symptoms in relation to specific and short-term stressors (n = 1),95 requiring inpatient admission but there was no available bed (n = 1),37 or receiving medical treatment for a suicide attempt (n = 1).97
Patients were excluded from admission if they were under the influence of or dependent on drugs or alcohol,90,97 aggressive or displaying non-stable behaviour,79,92,93 had medical issues,79,90,92,93 resided outside of the catchment area,90,97 had a pattern of self-harming97 or required an inpatient admission.79,97
Units received referrals from the ED,40,45,79,90,92–94,96,97 the PES,91 other assessment and intervention units,37,92,94 outpatient clinics,79,94 other crisis services45,90 and other parts of the hospital.92 The units were most commonly staffed by psychiatrists,37,40,79,90,93–97 social workers,37,79,93,94,96 nurses,37,40,92,94,96 psychiatric nurses,79,93,96–97 and psychiatric technicians or nursing assistants.79,95 Units also employed: a psychologist,97 drug and alcohol clinicians,40 and high numbers of staff with knowledge of trauma-informed care.92 Some units described themselves as hosting a multidisciplinary team90,96 and having a high staff-to-patient ratio.92
Quality rating of included studies
Quality rating of each outcome of interest, for each study, are given for randomised (see Figure 4) and non-randomised studies (see Figure 5).
FIGURE 4 Risk of bias ratings for outcomes from randomised studies. (Figure not reproduced here; see the original article.)
FIGURE 5 Risk of bias ratings for outcomes from non-randomised studies. Sources: Parwani et al.,37 Braitberg et al.,40 Tretheway et al.,45 Stamy et al.,79 Browne et al.,90 Gillig et al.,91 Kealy-Bateman et al.,92 Lester et al.,93 Mok and Walker,94 Schneider and Ross95 and Spooren et al.96 (Figure not reproduced here; see the original article.)
We extracted 41 outcomes from 11 non-randomised studies, and four outcomes from a single RCT.97 First, looking at the non-randomised studies, as indicated in Figure 5, we assessed there to be moderate risk of bias in a majority of outcomes considered in the review (27/41), from across most included studies (7/12). The most prevalent source of bias was potential bias in selection of reported result (in the absence of published protocols for most studies it was not clear that the full range of outcomes assessed in studies had been analysed and reported). Three outcomes from two studies91,95 were assessed as of serious risk of bias due to the risk of bias from confounding as the comparison groups were considered to be defined in a way which suggests that they are too dissimilar. Three further outcomes were at critical risk of bias because of additional biases identified or the bias due to confounding being rated as critical. Seven outcomes from one study79 were assessed as of low risk of bias. In the single RCT,97 two outcomes were assessed as of some concerns because of potential bias arising from the randomisation process, and two further outcomes of high concern because of, in addition, bias due to missing outcome data.
Synthesis of outcomes
Total emergency department length of stay
All four studies assessing total LOS in ED reported a significant reduction in this outcome.37,40,80,94 Lester et al.93 reported a mean decrease from 14.48 to 11.11 hours (p < 0.001), employing mixed model analysis using log-transformed ED lengths of stay. Parwani et al.37 reported a reduction in median ED LOS from 155 minutes [interquartile range (IQR) 19–346] to 35 minutes (IQR 9–209) with autoregressive integrated moving-average modelling indicating this difference to be highly significant (p < 0.0001). Braitberg et al.40 reported a reduction in median LOS from 328 minutes (IQR 227–534) in the pre-PDU period to 180 minutes (IQR 101–237; p < 0.001) in the post-PDU period, and Stamy et al.79 a reduction from 351 minutes (IQR 204–631) to 334 minutes (IQR 212–517); a mean difference of 114 minutes (95% CI 87 to 143).
Where possible, data for ED lengths of stay were combined meta-analytically using mean difference random-effects models, with a pooled estimate for a reduction in total ED LOS of 164.24 minutes (95% CI −261.24 to −67.23 minutes; p < 0.001). The data from two studies could not be combined meta-analytically as one study did not report a measure of variance93 and another reported only reported medians.37 An I2 of 98% indicated high heterogeneity (see Figure 6). A GRADE starting rating of ‘low certainty, confidence or quality’ for outcomes of meta-analyses of non-randomised studies was upgraded to ‘moderate certainty’ due to the ROBINS-I ratings, indicating that authors believe that the true effect is probably close to the estimated effect.
FIGURE 6 Forest plot of total length of ED stay in minutes. Sources: Braitberg et al.40 and Stamy et al.79 (Figure not reproduced here; see the original article.)
Emergency department wait time
One study40 reported a reduction in wait to be seen by a clinician in ED from a median of 68 minutes (IQR 24–130) in the control group to 40 minutes (IQR 17–86) in the experimental group (p < 0.001) and a reduction in median wait time for a mental health review from 139 minutes (IQR 57–262) to 117 minutes (IQR 49–224; p = 0.001). In another study,79 psychiatric boarding – time waiting in ED for a bed or transfer – decreased from 212 minutes (SD 119–536) to 152 minutes (SD 86–307) (mean difference 189 minutes; 95% CI 50 to 228). A reduction in long waits in ED was reported by one study,90 down from 12 patients per month who waited in ED for at least 24 hours in the pre-PDU opening period to only six 24-hour waits in the entire post-PDU period.
Emergency department environment: use of security services and restraint
Two studies40,90 assessed changes in adverse violent or threatening events that require a formal response from a security team (code grey events) and restrictive interventions from the pre- to post-PDU periods, although neither study was of high quality. Braitberg et al.40 reported a reduction in events from 538 to 349 (p = 0.003) and a reduction in number of patients involved from 370 to 259 (p = 0.159). Browne et al.90 reported a reduction in events in the ED but this was accompanied by an increase in events in the linked unit. Braitberg et al.40 reported a reduction in number of patients experiencing any restrictive intervention from 338 patients (12.7%) to 255 patients (10.7%; p = 0.02), reduction in number of physical restraints from 339 (11.3%) to 224 (9.4%; p = 0.04), reduction in mechanical restraint from 275 (9.0%) to 156 (6.6%; p < 0.001) and reduction in use of therapeutic sedation from 250 (8.2%) to 156 (6.6%; p < 0.001). Browne et al.90 reported a reduction in the total number of patients restrained from the pre- to post-PDU period, although size of cohort, total hours of restraint and average hours of restraint per patient were unclear.
Other emergency department outcomes
A single study79 reported no significant difference in the number of patients leaving ED without being seen between pre- and post-PDU opening periods, and similarly no difference in the combined number of patients leaving against medical advice. One study reported a reduction in numbers of patients brought to ED by street triage teams from the pre- to post-PDU opening periods but did not test this for significance.45
Psychiatric inpatient admissions
A number of studies reported the impact of the PDU on inpatient psychiatric admissions. Parwani et al.37 reported a significant reduction in the proportion of ED patients who experienced a psychiatric admission after the unit opened, from 42% to 25% (p < 0.001). Stamy et al.79 reported that 301 (8.3%) patients presenting to ED were admitted to inpatient psychiatry in the ‘post’ period compared to 509 (15.3%) patients in the ‘pre’ period, representing a difference of −7.0 (95% CI −8.5 to −5.5). Lester et al.93 reported that admissions to wards from ED reduced from 47.9% of presenting psychiatric patients to 38.0%, that discharge from ED rates were reduced by 39.1% to 28.2%, and that the total number of admissions to ward and transfers reduced from 58.8% to 50.9%. Gillig et al.91 reported that 35% (156/435) of the intervention group were hospitalised from either ED or the PDU compared with 52% (181/348) of the control group, but these outcomes were assessed as being at serious risk of bias due to differences between the sites and populations they served. Tretheway et al.45 reported that the number of patients admitted to a psychiatric ward by the ED-based liaison psychiatry team reduced from the pre- to post-PDU opening period but did not test for significance.
The data for psychiatric admissions from four studies where data were sufficiently well reported were combined meta-analytically (see Figure 7). As Gillig et al.91 was assessed to be at critical risk of bias, a sensitivity analysis was conducted excluding the study. The combined OR is 0.55 (95% CI 0.43 to 0.68), with an I2 value of 91%; data from 19,634 patients). The result was effectively unchanged in the sensitivity analysis (combined OR is 0.55; 95% CI 0.42 to 0.73, with I2 of 94%). The GRADE rating for outcomes for meta-analyses of non-randomised studies of ‘low certainty, confidence or quality’ was upgraded to ‘moderate certainty’ due to the ROBINS-I ratings, indicating that we believe that the true effect is probably close to the estimated effect.
FIGURE 7 Forest plot of inpatient psychiatric admissions. Sources: Parwani et al.,37 Stamy et al.,79 Gillig et al.91 and Lester et al.93 (Figure not reproduced here; see the original article.)
Psychiatric ward occupancy rates
Only one study94 reported data for occupancy rates for the ‘regular-stay unit’ as 94%, 98%, 99% and 95% in the pre-PDU period compared with 89%, 91%, 96% and 85% post PDU. The results are difficult to interpret as ‘regular-stay unit’ is not clearly defined, within month variance is not reported and no statistical analysis was conducted.
Length of psychiatric admission
One study93 reported a reduction in total time in hospital following ED presentation from a mean of 100.89 hours (median 46.15) hours to 91.00 hours (median 31.35), a significant reduction (p = 0.03) using log-transformed data in a mixed model. Van der Sande et al.97 reported no significant difference in total number of inpatient days when time spent on the experimental unit was included; 33 days (SD 73.5) in the active group compared with 37 days (SD 83.0) in the control group. However, when inpatient days were compared excluding time spent on the experimental unit the difference was significant (z = −5.51, p < 0.001).
Hospitalisation in the follow-up period
Lester et al.93 reported similar rates of hospitalisation across the groups following discharge from the unit (6.9% vs. 6.7%). Van der Sande et al.97 reported a reduction in the number of patients who had a psychiatric inpatient admission during a 1-year follow-up in the PDU group (24%) compared with 38% in the control group but did not test for significance. Schneider and Ross95 reported a 30-day readmission rate for participants who stayed in the intervention unit similar to other patient samples, but this was deemed to be at serious risk of bias as the comparison groups were not clearly defined.
Psychometric outcomes
No psychometric outcomes (symptom scales or patient-reported outcomes) showed significant difference between the groups. Spooren et al.96 (a study at moderate risk of bias) found no significant difference in scores on the General Health Questionnaire 2898 between groups at 1-month follow-up (t = –0.37, p = 0.715) or in the proportions of patients in each group who reported improvement in each group (t = 0.42, p = 0.677). Van der Sande et al.97 reported no significant in any of the general symptom index [F(8,112) < 1, p = 0.72], hopelessness scale [F(1,110) = 2.14, p = 0.15] or Symptom Checklist-90; [F(8,110) = 1.03, p = 0.42].
Suicidality
Only one study, which described an experimental unit designed for those who had attempted suicide, reported data about changes to suicidality.97 The study found that there was no significant difference in the number of suicide attempts per patient in the follow-up period (Z = 0.49, p = 0.62) and no difference in the probability of repeat suicide attempts in the follow-up period (hazard ratio of repetition for patients in the experimental group compared with the care as usual group was 1.24 (95% CI 0.68 to 2.27). For patients identified as at high risk of a repeat suicide attempt (a score of at least four on the Buglass and Horton scale),99 there was a non-significant difference in repeat attempts between experimental and control groups (log rank 2.69; p = 0.10). However, when gender was controlled for, males in the experimental group were found to be significantly more likely to repeat the suicide attempt (log rank 4.28; p = 0.04). Significantly more patients in the experimental group received outpatient care (including care specifically connected to the PDU) in the first year of follow-up (χ2 = 37.42; df = 1, p < 0.001).
Deaths
Stamy et al.79 reported a decrease in deaths – in the ‘pre’ sample of 23,336 individuals there was one fatality and in the ‘post’ sample (23,231 patients) there were no fatalities – but a power calculation was not reported and the result is unlikely to have sufficient power for conclusions to be drawn.
Health economic outcomes
Browne et al.90 reported an annual reduction in the cost of one-to-one nursing in ED for those presenting with psychiatric problems of A$129,000, congruent with a reduction in time spent in ED and a decrease in the number of hours of one-to-one nursing care in the first 3 months after the unit fully opened compared with the same period in the previous year. However, no denominator or significance test was reported for this analysis. In the United States, Stamy et al.79 reported additional revenue for the ED as a result of the experimental unit opening of US$404,954 in the 6 months and $861,065 annually.
Appraisal of findings
The main source of variation in quality was found in the way in which the control group was defined. There were also differences in populations, including differences in the study setting and surrounding health and social care services; it is worth noting that all studies were conducted in high-income countries. Many studies reported similar types of results, but differences in reporting – especially of events data – limited the number of meta-analyses we could perform. Studies reporting median with IQR (and not mean values) also limited how many studies could be included in meta-analyses. Selective reporting, in which studies have reported only outcomes of particular interest to their unit or only positive outcomes, is possible. Although this review included non-randomised studies, the quality of these was carefully scrutinised using the ROBINS-I tool. Many studies were of moderate quality and only one included study received the highest quality rating; as such we should be cautious about the results.