World health system performance revisited: the impact of varying the relative importance of health system goals

Background

In 2002, the World Health Organization published a health system performance ranking for 191 member countries. The ranking was based on five indicators, with fixed weights common to all countries.

Methods

We investigate the feasibility and desirability of using mathematical programming techniques that allow weights to vary across countries to reflect their varying circumstances and objectives.

Results

By global distributional measures, scores and ranks are found to be not very sensitive to changes in weights, although differences can be large for individual countries.

Conclusions

Building the flexibility of variable weights into calculation of the performance index is a useful way to respond to the debates and criticisms appearing since publication of the ranking.     

Value of power doppler and 3D vascular sonography as a method for diagnosis and staging of prostate cancer

OBJECTIVES: To compare the value of Power Doppler Sonography (PDS) and B mode sonography in the diagnosis of prostate cancer and to assess the value of PDS to specify capsular effraction of the cancer. PATIENTS AND METHODS: 323 patients were investigated: 41 control subjects allowed the establishment of normal vascular semiology and 282 patients with suspected cancer (PSA >4ng/ml). Power Doppler Sonography with 3D reconstruction was used to describe Power Doppler Sonography features of normal or abnormal vessels. Three types of blood supply(a: regular avascular posterior peripheral margin, b: irregular avascular posterior peripheral margin, c: vessels crossing the posterior peripheral margin) were described as a function of the presumed stage of cancer (a: intraprostatic, b: undetermined, c: extraprostatic). Comparison with histology was performed on random biopsies without Doppler (282 cases) (median PSA level = 15.8ng/ml), on second biopsies indicated with PDS (72 cases), and radical prostatectomy specimens (63 cases). RESULTS: A cancer was diagnosed in 157 of the 282 patients (55.7%) with suspected cancer. The overall sensitivity of PDS in the initial diagnosis of prostatic cancer was 92.4% and its specificity was 72% (versus 87.9% and 57.6% for sonography alone respectively). The negative predictive value of PDS was elevated to 80.6% (p<0.0001). Targeting area presenting abnormal blood flow in any part of the prostate was useful to detect isoechoic or lesions in patients with first negative biopsy results (in 41 of 72 targeted patients with first negative biopsies with PDS a cancer was diagnosed: 58% of these cancers had less than 3 positive biopsies and 34% only one positive biopsy). The 3 vascular types a, b, c were evaluated prospectively in the detection of capsular effraction. The presence or absence of vessels crossing the capsule to determine an extracapsular extension was a significant sign (p<0.0001). Capsular effraction was detected in 3 of the 27 cases (11%) of type a cancer and in 16 of the 18 cases (87%) of type c cancer. CONCLUSION: PDS improves the accuracy of echographic imaging in the diagnosis of cancer. Combining first sextant biopsies and targeted areas presenting abnormal blood flow using PDS can increase cancer detection with an optimized number of biopsy cores. The risk of extracapsular involvement can be evaluated by the presence of vessels perforating the capsule.     

A generic model for the assessment of disease epidemiology: the computational basis of DisMod II

Reliable and comparable analysis of risks to health is key for preventing disease and injury. Causal attribution of morbidity and mortality to risk factors has traditionally been conducted in the context of methodological traditions of individual risk factors, often in a limited number of settings, restricting comparability.     

Population health metrics: crucial inputs to the development of evidence for health policy

Valid, reliable and comparable measures of the health states of individuals and of the health status of populations are critical components of the evidence base for health policy. We need to develop population health measurement strategies that coherently address the relationships between epidemiological measures (such as risk exposures, incidence, and mortality rates) and multi-domain measures of population health status, while ensuring validity and cross-population comparability.     

Bioactive acridone alkaloids from Swinglea glutinosa

A new prenylated acridone alkaloid, 1,3,5-trihydroxy-2,8-bis(3-methylbut-2-enyl)-10-methyl-9-acridone (1), was isolated from the stembark of Swinglea glutinosa, along with three known acridone alkaloids, 5-hydroxynoracronycine (2), 1,3,5-trihydroxy-4-methoxy-2-(3-methylbut-2-enyl)-10-methyl-9-acridone (3), and 1,3,5-trihydroxy-4-methoxy-10-methylacridone (4). The isolated alkaloids were assessed in vitro against chloroquine-sensitive and -resistant Plasmodium falciparum strains and for cytotoxicity using HeLa cells.     

Breast and cervical cancer survival: making sense of ‘league tables’

During 1998, the Department of Health proposed to use survival rates of cervical and breast cancer in the 1989/90 incidence cohort as indicators of care. Valid interpretation was of concern within Trent and the Trent Cancer Registry responded by performing additional analyses. Trent Cancer Registry registrations for 1989/90 were re-analysed and the stability of districts' ranks for that cohort was investigated using random simulation techniques. Stability of ranks across more recent cohorts was investigated and attempts made to use all available information.The Department of Health's analyses were confirmed by our re-analysis of the 1989/90 cohort: Rotherham residents appeared to have the "worst" survival for cervical cancer, and Sheffield residents for breast cancer, although not statistically significantly so. Random simulations indicated that ranks based on a single cohort are not stable: for example Sheffield (ranked tenth for 1-y breast cancer survival) was ranked third or better in 6% of randomisations. Ranks were also unstable across cohorts: for example Rotherham 1-y cervical cancer survival was ranked tenth for 1989/90, fifth for 1991/92 and tenth for 1993/94. Analysis of 3-y running averages provided better information than the league table approach. Most districts improved over time, to different degrees, and similar sized gaps remained between the "best" and the "worst" districts. This analysis illustrates the need to be circumspect when interpreting "league tables" based on a single year or cohort analysis. League tables are based on ranks: clearly a large difference in rank may reflect only trivial (ie medically unimportant) differences in actual outcome. Lack of a statistically significant difference in survival between two districts does not mean their survival is equivalent. Even for a common cancer, like breast cancer, rankings were unstable from cohort to cohort. At the Registry we propose to perform these trend analyses routinely in future, adjusting, when possible, for the effects of deprivation and stage at diagnosis.     

Abnormal surfactant composition and activity in severe bronchiolitis

A prospective study of infants under 1 y of age, ventilated for severe viral bronchiolitis, was carried out in four paediatric intensive care units in order to study surfactant activity and composition in this condition. Lung lavage fluid from 24 infants with bronchiolitis, 19 with bronchiolitis and sepsis or cardiac failure and 12 controls were analysed by the “click test” for surfactant activity and for phospholipids. Surfactant activity was present in all controls, but in only 2 of the 24 infants with bronchiolitis alone. The presence of phosphatidylglycerol correlated perfectly with the click test, suggesting that reduced activity is due to changes in surfactant lipid composition. In those with bronchiolitis plus coexisting disease, surfactant activity and phosphatidylglycerol were absent in only half. Surfactant activity and phosphatidylglycerol re-appeared by extubation. Severe viral bronchiolitis is associated with an absence of surfactant activity and PG, which resolves by clinical recovery. Infants with coexisting conditions are not always surfactant deficient. Surfactant administration is likely to be beneficial, but requires a selective approach.