The search for stable prognostic models in multiple imputed data sets

Background  

In prognostic studies model instability and missing data can be troubling factors. Proposed methods for handling these situations are bootstrapping (B) and Multiple imputation (MI). The authors examined the influence of these methods on model composition.     

The COSMIN checklist for evaluating the methodological quality of studies on measurement properties: A clarification of its content

Background  

The COSMIN checklist (COnsensus-based Standards for the selection of health status Measurement INstruments) was developed in an international Delphi study to evaluate the methodological quality of studies on measurement properties of health-related patient reported outcomes (HR-PROs). In this paper, we explain our choices for the design requirements and preferred statistical methods for which no evidence is available in the literature or on which the Delphi panel members had substantial discussion.     

Health care services utilization stratified by virological and immunological markers of HIV: evidence from a universal health care setting

Objective

The aim of the study was to determine rates of utilization of in‐patient, out‐patient and laboratory services stratified by virological and immunological markers of HIV disease among patients on antiretroviral treatment in British Columbia, Canada.

Methods

We estimated resource utilization for in‐patient visits, out‐patient visits, and laboratory tests among patients initiating antiretroviral treatment between 1 April 1994 and 31 December 2000, with follow‐up to 31 March 2001. Resource use was stratified by CD4 cell count and plasma HIV viral load (pVL) at the time of utilization and rates per 100 patient‐years were calculated for each health care resource.

Results

A total of 2718 patients were included in our analyses. The overall rates of in‐patient visits, out‐patient visits, and laboratory tests were 902, 3001 and 840 per 100 patient‐years, respectively. Utilization was higher for patients with low CD4 cell counts and high pVLs when compared with patients with high CD4 cell counts and low pVLs.

Conclusions

Patients with low CD4 cell counts and high pVLs had the highest use of health care services. Regular follow‐up with health care providers in an out‐patient setting, allowing for proper monitoring and maintenance of HIV care, is important in minimizing unnecessary and potentially costly in‐patient care.     

Double blind placebo controlled trial of nebulised budesonide for croup

AIMS: To determine whether nebulised budesonide improves the symptoms or shortens the duration of stay of children admitted to hospital with a clinical diagnosis of croup. METHODS: A prospective, randomised, double blind placebo controlled trial. Patients received either nebulised budesonide or placebo every 12 hours. The main outcome measures were duration of inpatient stay and croup scores at 30 minutes, one, two, four, 12, and 24 hours. RESULTS: 87 patients (89 admissions) aged 7-116 months entered the trial. Nebulised budesonide was associated with a significant improvement in symptoms at 12 hours (95% confidence interval (CI) 1 to 3) and 24 hours (95% CI 0 to 3). Patients with an initial croup score above 3 demonstrated a significant improvement in symptoms at two hours (95% CI 1 to 3). Nebulised budesonide was also associated with a 33% reduction in the length of stay (95% CI 2% to 63%) when the confounding variables of age, initial croup score, and coryzal symptoms were taken into consideration. CONCLUSIONS: Nebulised budesonide is an effective treatment for children admitted to hospital with a clinical diagnosis of croup.     

Invasive Haemophilus influenzae type b infections in children hospitalized in Hong Kong, 1986–1990

A 5-year territory-wide retrospective survey of invasive Haemophilus influenzae type b diseases was conducted in Hong Kong. Between 1986 and 1990, 57 cases (28 male) were recorded in children less than 12 years old (37 cases of meningitis, 9 of septicaemia and 11 of bacteraemic pneumonia). The annual incidence for children less than 5 years old was 2.7 per 10⁵ (95% confidence interval (CI) 2.0–3.5). Of the 57 cases, 39 were Chinese and 18 non-Chinese (7 Vietnamese refugees, 6 Caucasians, 5 others). The annual incidence in Vietnamese refugees less than 5 years old was 42.7 per 10⁵ (95% CI 17.2–87.9), giving a relative risk of 18.5 (95% CI 8.3–41.0). Chinese patients (68%) were under-represented as Chinese accounted for at least 94% of the population. Moreover, 14 of the 39 Chinese patients had pre-existing medical problems, compared with only 1 of the 18 non-Chinese patients (p = 0.022).     

Controlled ovarian hyperstimulation and intrauterine insemination for treating male subfertility: a controlled study

In this randomized crossover trial we investigated whether the use of controlled ovarian hyperstimulation with low-dose human menopausal gonadotrophin in couples with male subfertility leads to a higher probability of conception when intrauterine insemination (IUI) is applied. We also investigated whether the efficacy of IUI in natural or stimulated cycles was related to the severity of male subfertility. Seventy-four couples completed 308 treatment cycles. Thirteen pregnancies occurred after IUI in a natural cycle (pregnancy rate per completed cycle: 8.4%) and 21 after IUI in a stimulated cycle (pregnancy rate per completed cycle: 13.7%). The difference between the two treatment modalities was not statistically significant. The efficacy of IUI in stimulated cycles was related to the severity of the semen defect. In couples with a total motile sperm count < 10 x 10(6), ovarian stimulation did not improve treatment outcome, while it did in couples with a total motile sperm count > or = 10 x 10(6). Compared with the expected chance of conceiving spontaneously without treatment, both natural and stimulated cycles improved the probability of conception. We conclude that, for the group as a whole, ovarian stimulation did not improve the probability of conception. However, in couples with less severe semen defects, ovarian stimulation did improve the probability of conception.