Duration of illness in ambulatory children diagnosed with bronchiolitis

OBJECTIVES

To measure the duration of illness in ambulatory children diagnosed with bronchiolitis and to examine clinical predictors of duration of illness.

DESIGN

Validation inception cohort study. Duration of follow up was 28 days.

SETTING

A primary-level ambulatory department of a public sector children's hospital in Cape Town, South Africa.

PATIENTS

One hundred eighty-one children aged 2 to 23 months who went to the hospital as their first contact for that episode of illness, and had a clinical diagnosis of bronchiolitis were enrolled consecutively on weekday mornings if their guardian stated that they were contactable by telephone.

MAIN OUTCOME MEASURE

Resolution of symptoms, as judged by the guardian, measured by twice-weekly telephone interviews.

RESULTS

Median duration of illness (calculated as the reported duration of symptoms before initial hospital visit plus the time from first consultation to recovery) was 12 days (95% confidence interval, 11-14 days). After 21 days, 18% were still ill and after 28 days, 9% were still ill. Sixty-two patients (34.2%) had unscheduled consultations within 28 days, a median of 13 days after the first consultation. There was no association of duration of illness with age, sex, z score for weight for age, or respiratory rate.

CONCLUSIONS

Ambulatory children diagnosed with bronchiolitis recover with few complications, but the resolution of symptoms may take several weeks. Providing parents with this information could help reduce the high rate of unscheduled return visits as observed in this cohort.

An effectiveness trial of a diagnostic test in a busy outpatients department in a developing country: issues around allocation concealment and envelope randomization

Methods to ensure allocation concealment in a randomized controlled trial in a busy outpatients department may disrupt usual clinical behavior, and thereby modify the effect of a diagnostic test. In a clinical trial of chest radiography in ambulatory children, concealment was maintained by means of sealed sequentially numbered manila envelopes. Baseline information was collected on all potential participants before they were presented to a clinician for a decision on inclusion in the trial. Excluded patients were followed up. Of 59 excluded patients, only 16 allocation envelopes had been opened or were not accounted for, although 12 of these had non-radiograph allocations (P = 0.05). There was no difference between patients excluded from radiograph and non-radiograph groups in baseline characteristics or primary outcome measure. Most of the improper exclusions occurred early in the study; improved monitoring and feedback reduced the problem. Sealed opaque sequentially numbered envelopes may be appropriate for trials of diagnostic tests in settings where centralized randomization is not feasible, and given careful monitoring of the enrollment process.

A randomised controlled trial of lay health workers as direct observers for treatment of tuberculosis

SETTING

Study conducted in a suburb of Cape Town, South Africa.

OBJECTIVE

Comparison of successful tuberculosis treatment outcome rates between self supervision, supervision by lay health worker (LHW), and supervision by clinic nurse.

METHODS

Open, randomised, controlled trial with intention-to-treat analysis.

RESULTS

All groups (n = 156) achieved similar outcomes (LHW vs. clinic nurse: risk difference 17.2%, 95% confidence interval [CI] -0.1-34.5; LHW vs. self supervision 15%, 95%CI -3.7-33.6). New patients benefit from LHW supervision (LHW vs clinic nurse: risk difference 24.2%, 95%CI 6-42.5, LHW vs. self supervision 39.1%, 95%CI 17.8-60.3) as do female patients (LHW vs. clinic nurse 48.3%, 95%CI 22.8-73.8, LHW vs. self supervision 32.6%, 95%CI 6.4-58.7).

CONCLUSIONS

LHW supervision approaches statistically significant superiority, but fails to reach it most likely due to the study's limitation, the small sample size. It is possible that subgroups (new and female patients) do well under LHW supervision. LHW supervision could be offered as one of several supervision options within TB control programmes.

[Meta-analysis of the Cochrane Collaboration. Promoting collaboration between nurses and physicians]

The aim of this systematic review of the Cochrane Collaboration was to assess the impact of interventions designed to change nurse-doctor collaboration on collaboration itself, on patient satisfaction, and on the effectiveness and efficiency of the health care provided. There are no good trials on interventions to improve collaboration between doctors and nurses. There are numerous strategies suggested to improve inter-disciplinary collaboration between doctors and nurses, such as joint workshops, meetings, development of team systems and strategies, and training in collaboration. However, no studies of these interventions that met the reviewers' criteria could be found. More research is needed to determine any impact of these strategies on interprofessional collaboration, and on the outcomes for patients.

Telephone follow-up in a randomized controlled trial in a less developed country: feasibility, validity and representativeness

Telephone follow-up would offer considerable advantages over other modes of follow-up in less developed countries, if it were feasible and the findings were valid and generalizable. Telephone follow-up was assessed in the context of a randomized controlled trial of chest radiography in South African children. Hospital-based clinical outcomes were measured from hospital records, and also by telephone, in a subset of the same patients who offered a contact telephone number. Of 398 subjects offering a telephone number 308 (77.4%) were followed to recovery or for 28 days. Kappa statistics for a subsequent hospital visit, hospital admission, and chest radiograph were 0.88, 0.83, and 0.56, respectively. The effect of chest radiography did not differ significantly in participants accessible and not accessible by telephone. Telephone follow-up was feasible and produced valid and generalizable results at low cost.

Interventions to promote collaboration between nurses and doctors

BACKGROUND

Lack of nurse-doctor collaboration contributes to problems in quality and efficiency of patient care.

OBJECTIVES

To assess the effects of interventions designed to improve nurse-doctor collaboration.

SEARCH STRATEGY

We searched the Cochrane Effective Practice and Organisation of Care Group specialised register and database of studies awaiting assessment, the Cochrane Database of Systematic Reviews, the Cochrane Controlled Trials Register, the Database of Abstracts of Reviews of Effectiveness, MEDLINE, and reference lists of articles up to the end of October 1999.

SELECTION CRITERIA

Randomised trials, controlled before-and-after studies and interrupted time series of interventions to improve collaboration between nursing and medical professionals sharing patient care in primary or hospital care settings.

DATA COLLECTION AND ANALYSIS

One reviewer assessed the eligibility of potentially relevant studies, extracted data and assessed the quality of included studies; a second reviewer undertook duplicate assessments on the eligibility of some articles and data abstraction on all included studies.

MAIN RESULTS

Two trials involving 1945 people were included. One six month trial involving 1102 admissions evaluated daily, structured, team ward rounds, in which nurses, doctors and other professionals made care decisions jointly. There was shortened average length of hospital stay (LOS) from 6.06 to 5.46 days, and reduced hospital charges from US$ 8090 to 6681. There were no differences in mortality rates or the type of care to which patients were discharged. Another three month trial involving 843 admissions compared two female wards and evaluated a four times per week round. There were no significant differences between the intervention and control wards in total average length of stay for all patients (11.7 days in intervention ward versus 11.6 in the control ward). Excluding patients who died in hospital revealed shortened length of stay in the intervention ward (intervention ward 10.5 days, control ward 11.9). Mortality rates were not significantly different.

REVIEWER'S CONCLUSIONS

Increasing collaboration improved outcomes of importance to patients and to health care managers. These gains were moderate and affected health care processes rather than outcomes. Further research is needed to confirm these findings. The logistic challenge presented by the complexity of the interventions and the need for large sample sizes due to the likely modest impact and rarity of outcome events may best be met by multi-centre studies. Before launching such studies qualitative research is needed to identify barriers to collaboration. Interventions other than nurse-doctor ward rounds and team meetings should also be tested.

Chest radiograph in acute respiratory infections in children

BACKGROUND

Chest radiography is widely used in acute lower respiratory infection in children, but the benefits are unknown.

OBJECTIVES

To assess the effects of chest radiography for children with acute lower respiratory infections.

SEARCH STRATEGY

We searched the Cochrane Respiratory Infections Group trials register, the Cochrane Controlled Trials Register and MEDLINE up to December 1999. We contacted experts in the fields of acute respiratory infections and paediatric radiology to locate additional studies.

SELECTION CRITERIA

Randomised or quasi-randomised trials of chest radiography in acute respiratory infections in children.

DATA COLLECTION AND ANALYSIS

One reviewer extracted data and assessed trial quality.

MAIN RESULTS

We identified only one trial of 522 participants, performed by the reviewers. The participants were ambulatory children aged two months to five years. Forty six percent of both radiography and control participants had recovered by seven days - odds ratio (1.03, 95% confidence interval 0.64 to 1.64). Thirty three percent of radiography participants and 32% of control participants made a subsequent hospital visit within four weeks - odds ratio 1.02 (95% confidence interval 0.71 to 1.48). Three percent of both radiography and control participants were subsequently admitted to hospital within four weeks - odds ratio 1.02 (95% confidence interval 0.40 to 2.60). There were no deaths in either group.

REVIEWER'S CONCLUSIONS

There is no evidence that chest radiography improves outcome in ambulatory children with acute lower respiratory infection. The findings do not exclude a potential effect of radiography, but the potential benefit needs to be balanced against the hazards and expense of chest radiography. The findings apply to ambulatory children only.

Randomised controlled trial of self-supervised and directly observed treatment of tuberculosis

BACKGROUND

Tuberculosis is a major public-health problem in South Africa, made worse by poor adherence to and frequent interruption of treatment. Direct observation (DO) of tuberculosis patients taking their drugs is supposed to improve treatment completion and outcome. We compared DO with self-supervision, in which patients on the same drug regimen are not observed taking their pills, to assess the effect of each on the success of tuberculosis treatment.

METHODS

We undertook an unblinded randomised controlled trial in two communities with large tuberculosis caseloads. The trial included 216 adults who started pulmonary tuberculosis treatment for the first time, or who had a second course of treatment (retreatment patients). No changes to existing treatment delivery were made other than randomisation. Analysis was by intention to treat. Individual patient data from the two communities were combined.

FINDINGS

Treatment for tuberculosis was more successful among self-supervised patients (60% of patients) than among those on DO (54% of patients, difference between groups 6% [90% CI -5.1 to 17.0]). Retreatment patients had significantly more successful treatment outcomes if self-supervised (74% of patients) than on DO (42% of patients, difference between groups 32% [11%-52%]).

INTERPRETATION

At high rates of treatment interruption, self-supervision achieved equivalent outcomes to clinic DO at lower cost. Self-supervision achieved better outcomes for retreatment patients. Supportive patient-carer relations, rather than the authoritarian surveillance implicit in DO, may improve treatment outcomes and help to control tuberculosis.

Underrecognition and undertreatment of asthma in Cape Town primary school children

BACKGROUND

In view of the high local prevalence of asthma, the extent of recognition and appropriate management of childhood asthma was studied in a large suburban area of Cape Town.

DESIGN

Cross-sectional study based on random community sample of schools.

METHOD

1,955 parents of sub B pupils from 16 schools completed a questionnaire, followed by: (i) an interview of the parents of 348 symptomatic children; and (ii) bronchial responsiveness testing on 254 children. The final case group consisted of 242 children with reported asthma or multiple asthma symptoms on both questionnaires. Children in whom asthma was acknowledged were compared with those in whom it was not.

RESULTS

Overall, any past or current ('ever') asthma was acknowledged by respondents in only 53% of the children, and current asthma in only 37.1%. While most children had received treatment in the previous 12 months, 66.1% of the recognised group were on current treatment (23.2% on daily treatment), compared with 37% of the unrecognised group (3% daily). Salbutamol and theophylline syrups were the most common types of medication, while inhalers and anti-inflammatory medications were underused. Only a minority of parents reported the child ever having used a peak flow meter, or volunteered knowledge of preventive measures. Current treatment, and to a lesser degree recognition of asthma by parents, were more common among children on medical aid and of higher socio-economic status.

CONCLUSIONS

These findings suggest that ways need to be found: (i) to increase the use of current asthma treatment guidelines by practitioners; (ii) to provide access to comprehensive care by children not on medical aid; and (iii) to improve education of parents in home management measures such as severity assessment and avoidance of smoking, allergen and dietary triggers.

Randomised controlled trial of clinical outcome after chest radiograph in ambulatory acute lower-respiratory infection in children

BACKGROUND

When available, chest radiographs are used widely in acute lower-respiratory-tract infections in children. Their impact on clinical outcome is unknown.

METHODS

522 children aged 2 to 59 months who met the WHO case definition for pneumonia were randomly allocated to have a chest radiograph or not. The main outcome was time to recovery, measured in a subset of 295 patients contactable by telephone. Subsidiary outcomes included diagnosis, management, and subsequent use of health facilities.

FINDINGS

There was a marginal improvement in time to recovery which was not clinically significant. The median time to recovery was 7 days in both groups (95% CI 6-8 days and 6-9 days in the radiograph and control groups respectively, p=0.50, log-rank test) and the hazard ratio for recovery was 1.08 (95% CI 0.85-1.34). This lack of effect was not modified by clinicians' experience and no subgroups were identified in which the chest radiograph had an effect. Pneumonia and upper-respiratory infections were diagnosed more often and bronchiolitis less often in the radiograph group. Antibiotic use was higher in the radiograph group (60.8% vs 52.2%, p=0.05). There was no difference in subsequent use of health facilities.

INTERPRETATION

Chest radiograph did not affect clinical outcome in outpatient children with acute lower-respiratory infection. This lack of effect is independent of clinicians' experience. There are no clinically identifiable subgroups of children within the WHO case definition of pneumonia who are likely to benefit from a chest radiograph. We conclude that routine use of chest radiography is not beneficial in ambulatory children aged over 2 months with acute lower-respiratory-tract infection.

A flow diagram to facilitate selection of interventions and research for health care

Decisions about health care should be informed by systematic review of valid research evidence on the effects of interventions on health outcomes that matter. If systematic review suggests it is likely that a health care intervention does more good than harm in some settings, questions must be addressed about the local applicability of the intervention, its cost-effectiveness, and feasibility of implementation. If systematic review suggests that it is unlikely that an intervention does more good than harm in any setting, its use should be discouraged, while existing interventions are improved or alternative interventions developed. If it is uncertain whether an intervention does more good than harm, further analysis of existing data or new controlled trials are required. The article contains a flow diagram, which provides a structure for making such decisions.

Most patients attending a 'walk-in' clinic at Red Cross War Memorial Children's Hospital could safely be managed at primary care level

OBJECTIVES

(i) To ascertain what proportion of patients attending the general medical outpatient service at Red Cross War Memorial Children's Hospital (RXH) could safely be managed at peripheral primary care facilities; and (ii) to measure the effect of the introduction of free health care for children under 6 years of age on requirements for levels of care ranging from home to super-specialist referral centres.

DESIGN

Prospective survey of patients attending on a stratified, randomised sample of 7 days in March 1994 (N = 1 962) and again in November 1994 (N = 1 404)-before and after the introduction on 6 June 1994 of free care for children under 6 years of age.

SETTING

The general outpatient department of an academic/referral children's hospital.

PATIENT SELECTION

All patients attending the outpatient department on the study days (7h00 to 6h59 the following day), excluding those who were referred, returning for follow-up, attending a specialist clinic or attending the surgical outpatient department. QUESTIONNAIRE: The questionnaire completed by medical officers recorded the following: patient's name, folder number, date and time of arrival, whether referred, clinic, treating doctor, disposal, diagnoses, home suburb and the level of care required: (i) home: (ii) clinic without a doctor; (iii) clinic with a doctor; (iv) hospital with non-specialists; (v) hospital with general paediatricians; or (vi) super-specialist hospital.

MAIN RESULTS

In March 1994 the percentages of unreferred patients requiring the 6 levels of care defined for the study were 0.3, 25, 62, 8, 3 and 1, respectively. In November 1994 the percentages were 4, 41, 43, 8, 4 and 1. The graph of the number of patients seen at the outpatient department each month shows a large month-to-month variation but the trend is clearly towards an increase.

CONCLUSIONS

The general medical outpatient department at RXH provides care to a large number of children, 48% of whom are unreferred. Of the unreferred patients 95% could be treated (more appropriately for the health services and more conveniently for their families) at a local primary health care facility. The situation has been aggravated by the introduction of free care for children under 6 years of age, who constitute 83% of the unreferred workload.

Risk factors for childhood asthma and wheezing. Importance of maternal and household smoking

To identify modifiable risk factors for wheezing illness in childhood, the associations between current asthma or wheezing and factors such as household smoking, damp and dietary salt preference were measured in a questionnaire-based prevalence study of schoolchildren 7 to 9 yr of age in Cape Town. In a random sample of 15 schools, questionnaires were completed by parents of 1,955 children, from which 368 cases and 294 controls were selected on the basis of reported asthma diagnosis or symptoms. Urinary cotinine concentrations were measured, and the parents were interviewed. An exposure-response relationship between the urinary cotinine creatinine ratio and asthma/wheeze was observed. In multivariate analysis, predictors of asthma/wheeze were hay fever (odds ratio [OR] - 5.30; 95% confidence interval [CI] = 3.16 to 8.89), eczema (OR = 2.19; 95% CI = 1.33-3.62), parental asthma (OR = 1.77; 95% CI = 1.11 to 2.84), absence of paternal contribution to income (OR = 1.72; 95% CI = 1.17 to 2.54), maternal smoking in pregnancy (OR = 1.87; 95% CI = 1.25 to 2.81), and each additional household smoker (OR = 1.15; 95% CI = 1.01 to 1.30). Findings were similar, with higher odds ratios for most variables, except number of household smokers, when the group was restricted to children with parent-reported asthma. The findings confirm that household smoking is an important modifiable risk factor in asthma/wheeze among young schoolchildren, and they suggest that maternal smoking in pregnancy and current household exposure are independent contributors to this effect.

Prevalence of psychiatric morbidity in the adult population of a rural South African village

We report on the first South African two-stage community prevalence study of psychiatric morbidity, conducted in Mamre, a rural "coloured' village, 50 km from Cape Town. Randomly selected adults (N = 481) were assessed using the Self-Reporting Questionnaire (SRQ) as a first-stage screen and the Present State Examination (PSE-9) was administered to a proportion of the sample (N = 121) as the second-stage criterion. Demographic, health care utilization, and substance abuse data were also collected. Using the PSE-9 CATEGO Index of Definition of 5, the weighted prevalence of psychiatric morbidity was 27.1% (confidence interval of 19.5-34.7%), the majority of cases being given a tentative diagnosis of depressive or anxiety disorder. The CATEGO algorithm may not be fully appropriate in this cultural context as there was an apparent over-diagnosis of paranoid states. The SRQ's weighted sensitivity and specificity were 0.49 and 0.82 respectively. Overall, the SRQ correctly identified 67% of cases and non-cases. No demographic variables predicted psychiatric morbidity, but there was an indirect link between morbidity and primary care utilization. Further South African studies of the validity of both the SRQ and of criterion instruments are needed. These may contribute to knowledge regarding cultural factors affecting psychiatric diagnosis.

Prevalence and reliability of asthma symptoms in primary school children in Cape Town

BACKGROUND

Childhood asthma is believed to be a serious problem in Cape Town, South Africa. This study aimed to measure the prevalence and reliability of asthma symptoms and reported asthma in Cape Town schoolchildren aged mainly 7 and 8 years, and to assess underdiagnosis.

METHOD

A questionnaire was completed by parents of 1955 children, followed by 620 personal interviews repeating the questions.

RESULTS

The prevalence of recent wheeze (previous 12 months) (26.8%) was high by international comparison, but not that of reported asthma (10.8%). Among children with more than 12 recent attacks of wheeze, only 60% were reported as asthmatic and 55% as receiving regular treatment. Symptom prevalences varied with the respondent's familial relationship to the child. On some questions the interview produced higher wheeze prevalences than the self-administered questionnaire. Repeatability of questions varied: asthma over (kappa = 0.69), recent wheeze (kappa = 0.59), and recent sleep disturbance by wheeze (kappa = 0.56) were the most reliable.

CONCLUSIONS

Prevalence based on symptom reports may vary with the respondent and between self- and interviewer-administered questionnaires. Also, certain questions currently proposed for childhood asthma questionnaires may be unreliable. Nevertheless, it can be concluded that the prevalence of wheeze is high in this population, and that underdiagnosis and undertreatment of asthma are a problem.

Is HIV/AIDS a primary-care disease? Appropriate levels of outpatient care for patients with HIV/AIDS

OBJECTIVE

To estimate the proportion of outpatient visits that could be managed at a primary-care level, by World Health Organization (WHO) clinical staging.

DESIGN

Prospective, descriptive study. Six medical doctors in a tertiary hospital HIV ambulatory clinic recorded clinical diagnoses, WHO clinical staging and their recommendation regarding the appropriate level of care for each outpatient seen.

SETTING AND STUDY POPULATION

All HIV-infected patients attending a public-sector, urban, South African, referral and teaching hospital HIV outpatient clinic between September and November 1992.

PARTICIPANTS

There were 238 visits by 148 patients during the study period.

RESULTS

Of 238 visits, 165 (69.3%) were deemed suitable for treatment at the primary-care level. After allowing for contradictory responses, at least 141 visits (59.2%) could be appropriately treated at the primary-care level. Although all six doctors assessed more than half of their visits as suitable for primary care, there were significant differences among them. In total, 83 visits (34.8%) needed a medical specialist, and 45 (18.9%) required tertiary-care facilities. Of all the visits, 58 (24.9%), 51 (21.9%), 60 (25.8%) and 64 (27.4%) were classified as WHO stages 1, 2, 3 and 4, respectively. For these stages, 55 (94.8%), 38 (74.5%), 42 (70.0%) and 26 (40.5%) visits, respectively, were suitable for treatment at a primary-care facility.

CONCLUSIONS

Many of the outpatient visits to this outpatient specialist clinic could have been safely cared for at a primary-care level. As the severity of the disease increases, there is a decrease in the proportion of patients that can be treated at a primary-care level.

Tuberculosis drug resistance in the Western Cape

OBJECTIVES

Drug resistance is a serious problem in the treatment of tuberculosis and a threat to successful tuberculosis control programmes. Local health workers have expressed concern that the increasing tuberculosis epidemic in the Western Cape is partly attributable to drug resistance. The aim of this study was to determine the prevalence of tuberculosis drug resistance (including multidrug resistance) and to investigate possible relationships between drug resistance and patient demographic characteristics.

DESIGN, SETTING, SUBJECTS, OUTCOME MEASURES

During a defined period, all adult (> or = 15 years) patients with pulmonary tuberculosis (confirmed by culture) from all tuberculosis clinics in the Western Cape were included. Previous tuberculosis treatment history was obtained by interviews, utilising a standardised questionnaire. Acquired drug resistance was determined on cultures from patients with a prior history of tuberculosis treatment, while initial resistance was determined from tuberculosis cases with no history of previous treatment.

RESULTS

Data from 7,266 patients were analysed. After adjusting for missing information by way of a random sample validation study, 32% of patients were found to have a history of previous treatment, 63% indicated no previous treatment, and in 5% the treatment history was unknown. Rates for initial resistance were found to be low at 3,9% for isoniazid, 1,1% for rifampicin and 0,2% for ethambutol. Combined resistance to isoniazid and rifampicin (multidrug resistance) was found to be 1,1% in patients not treated before. Acquired resistance rates were higher at 10,8% for isoniazid, 4,2% for rifampicin, 0,3% for ethambutol and 4,0% for multidrug resistance. Logistic regression analysis of the data indicated that drug resistance was not influenced by population group, gender or age. Patients with a history of tuberculosis treatment were found to be at an increased risk of developing drug resistance (relative risk 2,6). Some regions in the Western Cape had higher proportions of previously treated patients with consequent higher acquired resistance rates.

CONCLUSIONS

Results from this study indicated that drug resistance is currently not a major problem in the Western Cape, rates comparing favourably with those reported from developed countries and being much lower than those for developing countries. Every effort should therefore be made to maintain the status quo and to prevent the emergence of further resistance. The priority for tuberculosis control in the Western Cape should remain to limit transmission of the disease by reducing the infectious pool through improved cure of (especially) smear-positive cases.

The introverted medical school--time to rethink medical education

Curricular reform in the education of medical students is highlighted within the context of changing patterns of provision of health care. A number of industrialised countries' medical schools have accepted that they have a 'social contract' to respond to the health needs of the populations they serve. Such a contract, and the commitment to populations which it would necessitate, is also relevant in the South African context.

A national sentinel surveillance network for the measurement of ill-health in South Africa. A prerequisite for epidemiological research and health planning

Data on births, on deaths by cause and on morbidity are essential in planning appropriate health interventions, but the scarcity of these data in South Africa is striking. Some of the limitations of national mortality and morbidity data collection systems are reviewed. In order to improve the usefulness of vital statistical information, it is proposed that active disease monitoring be introduced in a number of surveillance sites where the population has been properly enumerated. A network of these sites would routinely gather information on births and deaths by cause and on a list of conditions that are: (i) easy to identify clinically; (ii) would bring most people to the attention of health personnel; and (iii) would indicate failure of health service provision, environmental control or resource allocation. The measurement of the geographical variation of a number of conditions, coupled with geographical information on health care indicators and risk and health promotive factors in each site, would facilitate the planning of interventions in a rational manner.