Avoiding hospital admission through provision of hospital care at home: a systematic review and meta-analysis of individual patient data

Reducing hospital bed use by frail older people: results from a systematic review of the literature

Introduction

Numerous studies have been conducted in developed countries to evaluate the impact of interventions designed to reduce hospital admissions or length of stay (LOS) amongst frail older people. In this study, we have undertaken a systematic review of the recent international literature (2007-present) to help improve our understanding about the impact of these interventions.

Methods

We systematically searched the following databases: PubMed/Medline, PsycINFO, CINAHL, BioMed Central and Kings Fund library. Studies were limited to publications from the period 2007-present and a total of 514 studies were identified.

Results

A total of 48 studies were included for full review consisting of 11 meta-analyses, 9 systematic reviews, 5 structured literature reviews, 8 randomised controlled trials and 15 other studies. We classified interventions into those which aimed to prevent admission, interventions in hospital, and those which aimed to support early discharge.

Conclusions

Reducing unnecessary use of acute hospital beds by older people requires an integrated approach across hospital and community settings. A stronger evidence base has emerged in recent years about a broad range of interventions which may be effective. Local agencies need to work together to implement these interventions to create a sustainable health care system for older people.

Internet video to support intravenous medication administration in the home: a cost minimisation study

We compared the costs associated with three different methods of administering antibiotics to paediatric oncology patients. In scenario A, medicine was prepared in the home, checked in the home using a video link to a second nurse, and administered in the home. In scenario B, medicine was prepared by outsourcing the work to a commercial organisation, checked by pharmacists off-site and administered in the home. In scenario C, medicine was prepared in the hospital, checked by a second nurse and administered in the outpatient department. The staff time required for home administration was calculated from actual home visits. The cost of tablet computers and mobile Internet charges for double-checks in the home was based on an assumed useful life of 3 years for the equipment. The cost of outsourcing the preparation of medications was calculated from the actual cost of doing so during a four month period. Patient outcome was assumed to be the same in all three scenarios. The mean costs of a medication episode (i.e. one occasion of medication administration) was $129.91 in scenario A, $312.00 in scenario B and $355.91 in scenario C. Nurse preparation and administration in the home would save the oncology health service $124,899 per annum compared to outsourcing medication preparation. Nurse preparation and administration in the home would save the oncology health service $155,329 per annum compared to nurse preparation and administration in the outpatient department. Use of Internet-based video appears to produce savings compared to other methods of administering antibiotics and the technique may have wider application in supporting complex interventions in the home.

The choice of alternatives to acute hospitalization: a descriptive study from Hallingdal, Norway

BACKGROUND

Hallingdal is a rural region in southern Norway. General practitioners (GPs) refer acutely somatically ill patients to any of three levels of care: municipal nursing homes, the regional community hospital or the local general hospital. The objective of this paper is to describe the patterns of referrals to the three different somatic emergency service levels in Hallingdal and to elucidate possible explanations for the differences in referrals.

METHODS

Quantitative methods were used to analyse local patient statistics and qualitative methods including focus group interviews were used to explore differences in referral rates between GPs. The acute somatic admissions from the six municipalities of Hallingdal were analysed for the two-year period 2010-11 (n = 1777). A focus group interview was held with the chief municipal medical officers of the six municipalities. The main outcome measure was the numbers of admissions to the three different levels of acute care in 2010-11. Reflections of the focus group members about the differences in admission patterns were also analysed.

RESULTS

Acute admissions at a level lower than the local general hospital ranged from 9% to 29% between the municipalities. Foremost among the local factors affecting the individual doctor's admission practice were the geographical distance to the different places of care and the GP's working experience in the local community.

CONCLUSION

The experience from Hallingdal demonstrates that GPs use available alternatives to hospitalization but to varying degrees. This can be explained by socio-demographic factors and factors related to the medical reasons for admission. However, there are also important local factors related to the individual GP and the structural preparedness for alternatives in the community.

Peritoneal dialysis--current status and future challenges

Peritoneal dialysis is now a well established, mature treatment modality for advanced chronic kidney disease. The medium term (at least 5 year) survival of patients on peritoneal dialysis is currently equivalent to that of those on haemodialysis, and is particularly good in patients who are new to renal replacement therapy and have less comorbidity. Nevertheless the modality needs to keep pace with the constantly evolving challenges associated with the provision and delivery of health care. These challenges, which are gradually converging at a global level, include ageing of the population, multimorbidity of patients, containment of cost, increasing self care and environmental issues. In this context, peritoneal dialysis faces particular challenges that include multiple barriers to the therapy and unsatisfactory and poorly defined technique survival as well as limitations relating to intrinsic aspects of the therapy, such as peritoneal membrane longevity and hypoalbuminaemia. To move the therapy forward and favourably influence health-care policy, the peritoneal dialysis community needs to integrate their research effort more effectively by undertaking clinically meaningful studies-with a strong focus on technique survival--that are supported by multidisciplinary expertise in patient-centred outcomes, study design and analysis.

Development of a patient-centred care pathway across healthcare providers: a qualitative study

Background

Different models for care pathways involving both specialist and primary care have been developed to ensure adequate follow-up after discharge. These care pathways have mainly been developed and run by specialist care and have been disease-based. In this study, primary care providers took the initiative to develop a model for integrated care pathways across care levels for older patients in need of home care services after discharge. Initially, the objective was to develop pathways for patients diagnosed with heart failure, COPD and stroke. The aim of this paper is to investigate the process and the experiences of the participants in this developmental work. The participants were drawn from three hospitals, six municipalities and patient organizations in Central Norway.

Methods

This qualitative study used focus group interviews, written material and observations. Representatives from the hospitals, municipalities and patient organizations taking part in the development process were chosen as informants.

Results

The development process was very challenging because of the differing perspectives on care and different organizational structures in specialist care and primary care. In this study, the disease perspective, being dominant in specialist care, was not found to be suitable for use in primary health care because of the need to cover a broader perspective including the patient’s functioning, social situation and his or her preferences. Furthermore, managing several different disease-based care pathways was found to be unsuitable in home care services, as well as unsuitable for a population characterized by a substantial degree of comorbidity. The outcome of the development process was a consensus that outlined a single, common patient-centred care pathway for transition from hospital to follow-up in primary care. The pathway was suitable for most common diseases and included functional and social aspects as well as disease follow-up, thus merging the differing perspectives. The disease-based care pathways were kept for use within the hospitals.

Conclusions

Disease-based care pathways for older patients were found to be neither feasible nor sustainable in primary care. A common patient-centred care pathway that could meet the needs of multi- morbid patients was recommended.

Evolving prehospital, emergency department, and "inpatient" management models for geriatric emergencies

Alternative management methods are essential to ensure high-quality and efficient emergency care for the growing number of geriatric adults worldwide. Protocols to support early condition-specific treatment of older adults with acute severe illness and injury are needed. Improved emergency department care for older adults will require providers to address the influence of other factors on the patient's health. This article describes recent and ongoing efforts to enhance the quality of emergency care for older adults using alternative management approaches spanning the spectrum from prehospital care, through the emergency department, and into evolving inpatient or outpatient processes of care.

The effect of clinical interventions on hospital readmissions: a meta-review of published meta-analyses

BACKGROUND

The economic impact and ease of measurement of all-cause hospital readmission rates (HRR) have led to the current debate as to whether they are reducible, and whether they should be used as a publicly reported quality indicators of medical care.

OBJECTIVE

To assess the efficacy of broad clinical interventions in preventing HRR of patients with chronic diseases

METHOD

A meta-review of published systematic reviews of randomized controlled trials (RCTs) of clinical interventions that have included HRR among the patients' outcomes of interest.

MAIN FINDINGS

Meta-analyses of RCTs have consistently found that, in the community, disease management programs significantly reduced HRR in patients with heart failure, coronary heart disease and bronchial asthma, but not in patients with stroke and in unselected patients with chronic disorders. Inhospital interventions, such as discharge planning, pharmacological consultations and multidisciplinary care, and community interventions in patients with chronic obstructive pulmonary diseases had an inconsistent effect on HRR. MAIN STUDY LIMITATION: Despite their economic impact and ease of measurement, HRR are not the most important outcome of patient care, and efforts aimed at their reduction may compromise patients' health by reducing also justified re-admissions.

CONCLUSIONS

The efficacy of inhospital interventions in reducing HRR is in need of further study. In patients with heart diseases and bronchial asthma, HRR may be considered as a publicly reported quality indicator of community care, provided that future research confirms that efforts to reduce HRR do not adversely affect other patients' outcomes, such as mortality, functional capacity and quality of life. Future research should also focus on the reasons for the higher efficacy of community interventions in patients with heart diseases and bronchial asthma than in those with other chronic diseases.

Mental health system in Saudi Arabia: an overview

BACKGROUND

There is evidence that mapping mental health systems (MHSs) helps in planning and developing mental health care services for users, families, and other caregivers. The General Administration of Mental Health and Social Services of the Ministry of Health over the past 4 years has sought to streamline the delivery of mental health care services to health consumers in Saudi Arabia.

OBJECTIVE

We overview here the outcome of a survey that assessed the Saudi MHS and suggest strategic steps for its further improvement.

METHOD

The World Health Organization Assessment Instrument for Mental Health Systems was used systematically to collect information on the Saudi MHS in 2009-2010, 4 years after a baseline assessment.

RESULTS

Several mental health care milestones, especially provision of inpatient mental health services supported by a ratified Mental Health Act, were achieved during this period. However, community mental health care services are needed to match international trends evident in developed countries. Similarly, a larger well-trained mental health workforce is needed at all levels to meet the ever-increasing demand of Saudi society.

CONCLUSION

This updated MHS information, discussed in light of international data, will help guide further development of the MHS in Saudi Arabia in the future, and other countries in the Eastern Mediterranean region may also benefit from Saudi experience.

Costs for 'hospital at home' patients were 19 percent lower, with equal or better outcomes compared to similar inpatients

Hospitals are the standard acute care venues in the United States, but hospital care is expensive and can pose health threats for older people. Albuquerque, New Mexico-based Presbyterian Healthcare Services adapted the Hospital at Home® model developed by the Johns Hopkins University Schools of Medicine and Public Health to provide acute hospital-level care within patients' homes. Patients show comparable or better clinical outcomes compared with similar inpatients, and they show higher satisfaction levels. Available to Medicare Advantage and Medicaid patients with common acute care diagnoses, this program achieved savings of 19 percent over costs for similar inpatients. These savings were predominantly derived from lower average length-of-stay and use of fewer lab and diagnostic tests compared with similar patients in hospital acute care. Hospital at Home advances the Triple Aim of clinical quality, affordability, and exceptional patient experience.

Avoidable emergency admissions?

BACKGROUND

Use of specialist healthcare services is increasing.

AIM

To evaluate whether alternative healthcare services could reduce the need for admissions to specialist care hospitals.

DESIGN

Prospective observational study of emergency referrals for admission to specialist care.

SETTING

A single out-of-hours primary care centre (OPCC) in Norway.

METHOD

Out-of-hours physicians registered their referrals for hospital admission and stated whether the admission could have been avoided given the availability of six other healthcare services.

RESULTS

Of 1083 registered encounters at the OPCC, 152 (14%) were referred for specialist care hospital admission. According to the referring physician, 32 (21%) of these referrals could have been avoided. The most eligible alternatives to such referrals were next-day appointments at a specialist outpatient clinic (11 of 32 referrals), or admission to a community hospital (21 of 32 referrals), or a nursing home (nine of 32 referrals). Respiratory (eight of 32 referrals) and gastrointestinal problems (12 of 32 referrals) were the most common among avoidable admissions.

CONCLUSIONS

The use of specialist care hospital admission can be reduced if appropriate alternatives are available.

Patients with acute exacerbation of chronic obstructive pulmonary disease feel safe when treated at home: a qualitative study

BACKGROUND

The design of new interventions to improve health care for patients with chronic obstructive pulmonary disease (COPD) requires knowledge about what patients with an acute exacerbation experience as important and useful. The objective of the study was to explore patients' experiences of an early discharge hospital at home (HaH) treatment programme for exacerbations in COPD.

METHODS

Six exacerbated COPD patients that were randomised to receiving HaH care and three patients randomised to receiving traditional hospital care were interviewed in semi-structured in-depth interviews. Four spouses were present during the respective patients' interviews. The interviews were audio-taped, transcribed and analysed by a four-step method for systematic text condensing.

RESULTS

Despite limited assistance from the health care service, the patients and their spouses experienced the HaH treatment as safe. They expressed that information that was adapted to specific situations in their daily lives and given in a familiar environment had positive impact on their self-management of COPD.

CONCLUSION

The results contribute to increased knowledge and awareness about what the patients experienced as important aspects of a HaH treatment programme. How adapted input from health services can make patients with exacerbation of COPD feel safe and better able to manage their disease, is important knowledge for developing new and effective health services for patients with chronic disease.

Outpatient parenteral antibiotic therapy (OPAT) at home in Attica, Greece

Outpatient parenteral antibiotic therapy (OPAT) is considered to be a cost-effective and safe alternative treatment strategy to hospitalization. We retrospectively evaluated data regarding the demographic and treatment characteristics of patients that sought medical advice from a network of physicians performing house-call visits and who received OPAT at home during a 17-month period (May 2009 to September 2010) in Attica, Greece. A total of 91 patients (69.2 % females) received intravenous antibiotic therapy at home during the evaluated period. The mean age [± standard deviation (SD)] of the patients was 85.3 (± 9) years. The main indications were pneumonia [46 patients (50.5 %)], urinary tract infection [25 (27.5 %)], and gastrointestinal tract infection [9 (9.9 %)]. Of the patients, 76.4 % received a beta-lactam, 17.5 % a fluoroquinolone, 15.3 % an imidazole, 8.7 % an aminoglycoside, and 5.4 % a lincosamide. The cure rate was 72.5 % and mortality was 27.5 %. The mean duration (± SD) of intravenous antibiotic treatment was 4.7 (± 3.3) days. The mean cost per patient was <euro>637 and was comparable to the mean cost if the patient were to be hospitalized for the same infection. There was significant clinical effectiveness of OPAT at home in this mainly elderly population, at an acceptable cost.

Acute care for elders units produced shorter hospital stays at lower cost while maintaining patients' functional status

Acute Care for Elders Units offer enhanced care for older adults in specially designed hospital units. The care is delivered by interdisciplinary teams, which can include geriatricians, advanced practice nurses, social workers, pharmacists, and physical therapists. In a randomized controlled trial of 1,632 elderly patients, length-of-stay was significantly shorter-6.7 days per patient versus 7.3 days per patient-among those receiving care in the Acute Care for Elders Unit compared to usual care. This difference produced lower total inpatient costs-$9,477 per patient versus $10,451 per patient-while maintaining patients' functional abilities and not increasing hospital readmission rates. The practices of Acute Care for Elders Units, and the principles they embody, can provide hospitals with effective strategies for lowering costs while preserving quality of care for hospitalized elders.

The impact of early emergency department allied health intervention on admission rates in older people: a non-randomized clinical study

BACKGROUND

This study sought to determine whether early allied health intervention by a dedicated Emergency Department (ED) based team, occurring before or in parallel with medical assessment, reduces hospital admission rates amongst older patients presenting with one of ten index problems.

METHODS

A prospective non-randomized trial in patients aged sixty five and over, conducted in two Australian hospital EDs. Intervention group patients, receiving early comprehensive allied health input, were compared to patients that received no allied health assessment. Propensity score matching was used to compare the two groups due to the non-randomized nature of the study. The primary outcome was admission to an inpatient hospital bed from the ED.

RESULTS

Of five thousand two hundred and sixty five patients in the trial, 3165 were in the intervention group. The admission rate in the intervention group was 72.0% compared to 74.4% in the control group. Using propensity score probabilities of being assigned to either group in a conditional logistic regression model, this difference was of borderline statistical significance (p = 0.046, OR 0.88 (0.76-1.00)). On subgroup analysis the admission rate in patients with musculoskeletal symptoms and angina pectoris was less for those who received allied health intervention versus those who did not. This difference was significant.

CONCLUSIONS

Early allied health intervention in the ED has a significant but modest impact on admission rates in older patients. The effect appears to be limited to a small number of common presenting problems.

How dangerous is a day in hospital? A model of adverse events and length of stay for medical inpatients

BACKGROUND

Despite extensive research into adverse events, there is no quantitative estimate for the risk of experiencing adverse events per day spent in hospital. This is important information for hospital managers, because they may consider discharging patients earlier to alternative care providers if this is associated with lower risk, but other costs and benefits are similar.

METHODS

We model adverse events as a function of patient risk factors, hospital fixed effects, and length of stay. Potential endogeneity of length of stay is addressed with instrumental variable methods, using days and months of discharge as instruments. We use administrative hospital episode data for 206,489 medical inpatients in all public hospitals in the state of Victoria, Australia, for the year 2005/2006.

RESULTS

A hospital stay carries a 5.5% risk of an adverse drug reaction, 17.6% risk of infection, and 3.1% risk of ulcer for an average episode, and each additional night in hospital increases the risk by 0.5% for adverse drug reactions, 1.6% for infections, and 0.5% for ulcers. Length of stay is endogenous in models of adverse events, and risks would be underestimated if length of stay was treated as exogenous.

CONCLUSIONS

The results of our research contribute to assessing the benefits and costs of hospital stays-and their alternatives-in a quantitative manner. Instead of discharging patients early to alternative care, it would be more desirable to address underlying causes of adverse events. However, this may prove costly, difficult, or impossible, at least in the short run. In such situations, our research supports hospital managers in making informed treatment and discharge decisions.

Elderly persons' experiences of participation in hospital discharge process

OBJECTIVE

The purpose of this study was to describe older hospital patients' discharge experiences on participation in the discharge planning.

METHODS

A sample of 254 patients aged 80+ was interviewed using a questionnaire developed by the research team. Data were collected by face-to-face interviewing during the first two weeks following patients discharge from hospital.

RESULTS

In spite of their advanced age the patients in this study did express a clear preference for participation. However, there were no significant correlation between patients' wish for participation and experienced opportunity to share decisions. Hearing ability was the only significant factor affecting the chance to participate, whereas sociodemographic factors did not significantly affect on the likelihood participation the discharge process.

CONCLUSION

The actual practice of involving old people in the discharge process is not well developed as experienced by old patients themselves. The fact that factors like gender and education have little influence on participation in the oldest patients might be related to age; when you get old enough, old is all that is 'visible'.

PRACTICE IMPLICATIONS

To determine the extent of elderly patients' desire to participate, one must actively look for it both through research and in the hands-on process of discharge.

Enhancement of CURB65 score with proadrenomedullin (CURB65-A) for outcome prediction in lower respiratory tract infections: derivation of a clinical algorithm

Background

Proadrenomedullin (ProADM) confers additional prognostic information to established clinical risk scores in lower respiratory tract infections (LRTI). We aimed to derive a practical algorithm combining the CURB65 score with ProADM-levels in patients with community-acquired pneumonia (CAP) and non-CAP-LRTI.

Methods

We used data of 1359 patients with LRTI enrolled in a multicenter study. We chose two ProADM cut-off values by assessing the association between ProADM levels and the risk of adverse events and mortality. A composite score (CURB65-A) was created combining CURB65 classes with ProADM cut-offs to further risk-stratify patients.

Results

CURB65 and ProADM predicted both adverse events and mortality similarly well in CAP and non-CAP-LRTI. The combined CURB65-A risk score provided better prediction of death and adverse events than the CURB65 score in the entire cohort and in CAP and non-CAP-LRTI patients. Within each CURB65 class, higher ProADM-levels were associated with an increased risk of adverse events and mortality. Overall, risk of adverse events (3.9%) and mortality (0.65%) was low for patients with CURB65 score 0-1 and ProADM ≤0.75 nmol/l (CURB65-A risk class I); intermediate (8.6% and 2.6%, respectively) for patients with CURB65 score of 2 and ProADM ≤1.5 nmol/l or CURB classes 0-1 and ProADM levels between 0.75-1.5 nmol/L (CURB65-A risk class II), and high (21.6% and 9.8%, respectively) for all other patients (CURB65-A risk class III). If outpatient treatment was recommended for CURB65-A risk class I and short hospitalization for CURB65-A risk class II, 17.9% and 40.8% of 1217 hospitalized patients could have received ambulatory treatment or a short hospitalization, respectively.

Conclusions

The new CURB65-A risk score combining CURB65 risk classes with ProADM cut-off values accurately predicts adverse events and mortality in patients with CAP and non-CAP-LRTI. Additional prospective cohort or intervention studies need to validate this score and demonstrate its safety and efficacy for the management of patients with LRTI.

Trial Registration

Procalcitonin-guided antibiotic therapy and hospitalisation in patients with lower respiratory tract infections: the prohosp study; isrctn.org Identifier: ISRCTN: ISRCTN95122877

Integrating Physician Services in the Home: evaluation of an innovative program

OBJECTIVE

To evaluate a new program, Integrating Physician Services in the Home (IPSITH), to integrate family practice and home care for acutely ill patients.

DESIGN

Causal model, mixed-method, multi-measures design including comparison of IPSITH and non-IPSITH patients. Data were collected through chart reviews and through surveys of IPSITH and non-IPSITH patients, caregivers, family physicians, and community nurses.

SETTING

London, Ont, and surrounding communities, where home care is coordinated through the Community Care Access Centre.

PARTICIPANTS

A total of 82 patients receiving the new IPSITH program of care (including 29 family physicians and 1 nurse practitioner), 82 non-randomized matched patients receiving usual care (and their physicians), community nurses, and caregivers.

MAIN OUTCOME MEASURES

Emergency department (ED) visits and satisfaction with care. Analysis included a process evaluation of the IPSITH program and an outcomes evaluation comparing IPSITH and non-IPSITH patients.

RESULTS

Patients and family physicians were very satisfied with the addition of a nurse practitioner to the IPSITH team. Controlling for symptom severity, a significantly smaller proportion of IPSITH patients had ED visits (3.7% versus 20.7%; P = .002), and IPSITH patients and their caregivers, family physicians, and community nurses had significantly higher levels of satisfaction (P < .05). There was no difference in caregiver burden between groups.

CONCLUSION

Family physicians can be integrated into acute home care when appropriately supported by a team including a nurse practitioner. This integrated team was associated with better patient and system outcomes. The gains for the health system are reduced strain on hospital EDs and more satisfied patients.

Medically-managed Hospital in the Home: 7 year study of mortality and unplanned interruption

Background.Hospital in the Home (HIH) research is characterised by small samples in new programs. We sought to examine a large number of consecutive HIH admissions over many years in an established, medically-managed HIH service in to determine whether: (1) HIH is a safe and effective method of delivering acute hospital care, under usual operating conditions in an established unit; and (2) what patient, condition and treatment variables contribute to a greater risk of failure. Method.A survey of all patients admitted to a medically-managed HIH unit from 2000–2007. Results.A total of 3423 admissions to HIH were examined. Of these 2207 (64.5%) were admitted directly into the HIH from Emergency Department or rooms, with the remainder admitted from hospital wards. A total of 26 653 HIH bed days were delivered, with a mean of 9.3 nursing visits and 4.1 medical visits per admission. A total of 143 patients (4.2%) required an interruption via an unplanned return to hospital; 106 (3.1%) did not subsequently return to HIH. The commonest reasons for unplanned returns to hospital were: no clinical improvement; cardiac conditions; fever; breathlessness and pain. Patients over the age of 50, and those receiving intravenous antibiotic therapy, were more likely to require a return to hospital. Two patients died unexpectedly while in HIH, and a further three patients died unexpectedly after their unplanned return to hospital. This is a total unexpected mortality rate of 0.15%. Conclusion.This sample of HIH patients is five times the number of HIH patients ever enrolled in randomised trials studies of this area. Further, outcomes were achieved in ‘ordinary’ working conditions over a long time period. Care was completed without interruption (return to hospital) in 95.8% of all episodes. Interruption was associated with patients referred from inpatient wards, older patients, and patients who were treated with intravenous antibiotics. Patients referred from Emergency Departments experienced fewer interruptions. Nursing home residents were no more likely to require an interruption to their HIH care. What is known about the topic?Hospital in the Home is the delivery of acute hospital services to patients at home. There is no consensus on the best model of HIH. Studies of HIH have small sample sizes, so support for HIH is often qualified. What does this paper add?This paper describes activity and outcomes for 3423 consecutive patients admitted into a medically-managed HIH over 7 years. This represents an extensive long-term survey of HIH patient care outcomes. What are the implications for practitioners?Medically-managed HIH is able to deliver acute hospital care with low rates of unexpected mortality and unplanned returns to hospital. Trials using low frequency events such as mortality and delirium as outcomes will require very large samples, and such large trials are unlikely to occur. The impact of medically-managed HIH on access to acute hospital services for certain diagnostic groups could be significant and deserves further expansion. The concept of hospitalisation can be refined to include HIH.

Can we systematically review studies that evaluate complex interventions?

BACKGROUND TO THE DEBATE

The UK Medical Research Council defines complex interventions as those comprising "a number of separate elements which seem essential to the proper functioning of the interventions although the 'active ingredient' of the intervention that is effective is difficult to specify." A typical example is specialist care on a stroke unit, which involves a wide range of health professionals delivering a variety of treatments. Michelle Campbell and colleagues have argued that there are "specific difficulties in defining, developing, documenting, and reproducing complex interventions that are subject to more variation than a drug". These difficulties are one of the reasons why it is challenging for researchers to systematically review complex interventions and synthesize data from separate studies. This PLoS Medicine Debate considers the challenges facing systematic reviewers and suggests several ways of addressing them.