How to do (or not to do) ... Assessing the impact of a policy change with routine longitudinal data

A lack of good quality evidence on the effect of alternative social policies in low- and middle-income countries has been recently underlined and the value of randomized trials increasingly advocated. However, it is also acknowledged that randomization is not always feasible or politically acceptable. Analyses using longitudinal data series before and after an intervention can also deliver robust results and such data are often reasonably easy to access. Using the example of evaluating the impact on utilization of a change in health financing policy, this article explains how studies in the literature have often failed to address the possible biases that can arise in a simple analysis of routine longitudinal data. It then describes two possible statistical approaches to estimate impact in a more reliable manner and illustrates in detail the more simple method. Advantages and limitations of this quasi-experimental approach to evaluating the impact of health policies are discussed.     

Cost-effectiveness analysis of human resources policy interventions to address the shortage of nurses in rural South Africa

Recent policy recommendations have called for increased research efforts to inform the design of cost-effective interventions to address the shortage of health workers in rural areas. This paper takes forward the recent use of Discrete Choice Experiments to assess the effects of potential incentives to attract nurses to rural areas. The analysis relies on data collected in South Africa between August and November 2008. Effectiveness measures derived from Discrete Choice Experiments are combined in a Markov model to derive the long-term effects of policies, and costs are evaluated with secondary data. Measures involving the selection of more nursing students who are more likely to accept positions in rural areas are shown to be the most cost-effective interventions. If such policies could not be implemented, the next best options are to offer preferential access to specialist training to nurses willing to work in rural areas.     

Failure of a combined anti-histamine and anti-leukotriene treatment to suppress passive anaphylaxis in the guinea-pig

Ovalbumin was used to trigger passive systemic anaphylactic shock in guinea-pigs treated with serum provided by actively sensitized animals. Shock was characterized by bronchoconstriction and hypotension, accompanied by leukopenia and moderate thrombocytopenia. Neither aspirin, a cyclooxygenase inhibitor, FPL 55712, a peptido-leukotriene antagonist, nor their combination interfered with shock, under conditions where the selective histamine antagonist mepyramine, up to 20 micrograms/kg, suppressed bronchoconstriction. When the animals were treated with the beta-adrenergic antagonist propranolol, mepyramine lost its activity, even if combined with aspirin and FPL 55712. Lungs provided by the sensitized animals secreted histamine and formed thromboxane A2 when challenged with ovalbumin, but failed to do so when the lungs were collected after systemic shock; demonstrating that in vivo desensitization involves direct effects on the lungs. Parenchyma lung strips from the sensitized animals and lung strips and trachea from non-sensitized animals placed together in an organ bath contracted when exposed to the antigen in presence of mepyramine. The contraction of the sensitized strips was not affected by FPL 55712 nor by the lipoxygenase inhibitors nordihydroguarietic acid and BW755c, but the responses of the non-sensitized tissues were suppressed, demonstrating that, apart from peptido-leukotrienes, parenchyma lung strips from passively sensitized animals generate a leukotriene and histamine-independent contracting activity. Histamine and peptido-leukotrienes do not account for the totality of passive anaphylactic shock in the guinea-pig.     

Cytomegalovirus infection in children with Down syndrome in a day-care center in Brazil

This study evaluates the transmission of CMV infection in 120 children aged 1 to 15 years with Down syndrome who attended a day-care center for handicapped children in S?o Paulo, Brazil. A blood sample was obtained from each children at the beginning of the study for detection of IgG and IgM cytomegalovirus (CMV) antibodies by an immunofluorescence assay. Samples of saliva and urine were obtained every 3 months from the children with CMV antibodies to detect shedding of the virus by culture in human foreskin fibroblasts, by detection of pp65 CMV-antigen and by a nested PCR assay. The prevalence of anti CMV-IgG antibodies was 76.6% (92/120), and IgM anti-CMV antibodies were detected in 13% (12/92) of the seropositive children. During the first viral evaluation, CMV was detected in the urine and/or saliva in 39/90 (43.3%) of the seropositive children. In the second and third evaluations, CMV was detected in 41/89 (46%) and in 35/89 (39.3%) children, respectively. Detection of CMV was shown both in urine and saliva in 28/39 (71.8%), 19/41(46.3%) and 20/35 (57.1%) of the children excreting the virus, respectively. Additionally, in 3(3/4)9 (67.4%) of the excreters CMV could be demonstrated in urine or saliva in at least two out of the three virological evaluations carried out sequentially in a six month period. Of the 28 initially seronegative children, 26 were re-examined for anti-CMV IgG antibodies about 18 months after the negative sample; seroconversion was found in 10/26 (38.5%). Taking all 536 samples of urine or saliva examined by virus culture and pp65 antigen detection during the study into account, 159 (29.6%) were positive by virus culture and 59 (11%) gave a positive result with the pp65 assay. These data demonstrate the high prevalence of CMV shedding and the high risk of CMV infection in children with Down syndrome attending a day-care center for mentally handicapped patients. The virus culture was more sensitive than the pp65 CMV antigen assay for CMV detection in both urine and saliva samples.     

Positron emission tomography/computed tomography in lung cancer staging, prognosis, and assessment of therapeutic response

Positron emission tomography (PET)/computed tomographic scanning, using 18F-2-deoxy-D-glucose, complements conventional imaging evaluation of patients with lung cancer. The strength of PET scanning lies in the detection of nodal and extrathoracic metastases. PET scanning is also currently being studied in the assessment of prognosis and therapeutic response and has the potential to alter management of oncologic patients. This review will discuss the role of PET/computed tomographic scanning in the diagnosis, staging, and evaluation of prognosis and treatment response in patients with lung cancer.     

Narrow‐ and regular‐diameter implants in the posterior region of the jaws to support single crowns: A 3‐year split‐mouth randomized clinical trial

Objectives

The objective of this 3‐year split‐mouth randomized controlled clinical study was to compare narrow‐diameter implants (NDIs) to regular‐diameter implants (RDIs) in the posterior region of the jaws (premolars and molars) in regards to (i) the marginal bone level (MBL) and (ii) implant and prosthesis survival and success rates.

Material and Methods

A total of 22 patients were included in the study. Each patient received at least one implant of each diameter (Ø3.3 and Ø4.1 mm), placed either in the maxilla or mandible to support single crowns. A total 44 implants (22 NDIs and 22 RDIs) were placed and included in the study. Twenty‐one implants were placed in the premolar, whereas 23 were placed in molar areas. Radiographic evaluations to access the MBL were performed immediately after implant placement, 1 and 3 years after implant loading. Peri‐implant clinical variables including probing pocket depth (PPD) and bleeding on probing (BoP) were obtained after crown delivery, 1 and 3 years after loading. Furthermore, the survival and success rates of the implants and prosthesis were also evaluated.

Results

Twenty patients were able to complete the study. There was no statistically significant difference regarding MBL between groups at implant placement (p = .084), 1‐year (p = .794) and 3‐year (p = .598) time intervals. The mean peri‐implant bone loss at 3‐year follow‐up was ?0.58 ± 0.39 mm (95% CI: ?0.751 to ?0.409) and ?0.53 ± 0.46 mm (95% CI: ?0.731 to ?0.329) for NDIs and RDIs, respectively. BoP was present at 15% and 10% of NDIs and RDIs, respectively, at 3‐year follow‐up. PPD >5 mm was observed in 5% and 0% of the implants of NDIs and RDIs, respectively, at 3‐year follow‐up. At the 3‐year examination, the implant success rates were in the NDIs and RDIs sites, respectively, 95% and 100%. The corresponding values for prosthesis success rates were 90% for NDIs and 95% for RDIs.

Conclusion

The present study demonstrated that NDIs placed to support single crowns in the posterior region did not differ to RDIs in regards to MBL, implant survival, and success rates.