Statistical inference for continuous variables

L'infirmière pivot associée à une expérience de soins oncologiques positive et à une satisfaction accrue des patients

Contexte et objectifs

Un nombre croissant de résultats probants indique que l'infirmière pivot en oncologie (IPO) joue un rôle de premier plan dans l'optimisation des processus et des résultats de soins. Il faudra toutefois mener des études d'envergure pour comparer les perceptions de l'expérience de soins liés au cancer des patients traités par des infirmières pivots et de ceux qui n'ont pas bénéficié de ce type de suivi.

Méthodologie

Des participants (N = 2 858) traités au cours des six derniers mois dans un centre de traitement du cancer situé à Montréal, au Québec, et affilié à une université ont répondu au sondage sur la satisfaction des patients en traitement anticancéreux ambulatoire, c'est-à-dire le Ambulatory Oncology Patient Satisfaction Survey (AOPSS).

Résultats

L'expérience des soins oncologiques était significativement plus positives et la satisfaction plus élevée dans le groupe suivi par une infirmière pivot (n = 2 003) pour les six domaines de soins (différences moyennes de 3,32 à 8,95) et les quatre fonctions infirmières (différences moyennes de 5,64 à 10,39), comparativement au groupe sans IPO (n = 855).

Discussion

L'infirmière pivot joue un rôle important dans l'amélioration de l'expérience de soins et la satisfaction des patients. Les recherches futures devront explorer les potentielles relations de cause à effet entre les infirmières pivots, les processus de soins et les résultats des patients.

The nurse pivot-navigator associated with more positive cancer care experiences and higher patient satisfaction

Background and objectives

Growing evidence indicates that the nurse navigator-pivot (NN), is key to optimizing care processes and outcomes. However, large scale studies are needed to examine how patients exposed to NNs (as opposed to non-NN) differentially perceived their cancer care experiences.

Method

Participants (N = 2,858) treated for cancer in the last six months at university-affiliated cancer centres in Montréal, Québec, completed the Ambulatory Oncology Patient Satisfaction Survey (AOPSS).

Results

Cancer care experiences and satisfaction were significantly higher in the NN group (n = 2,003) for all six care domains (Ds from 3.32 to 8.95) and all four nursing functions (Ds from 5.64 to 10.39) when compared to the non-NN group (n = 855).

Discussion

The NN role is significantly related to enhanced cancer care experiences and higher patient satisfaction. Future research should explore potential causal effects between NNs and care processes, as well as patient outcomes.

Exploratory data analysis for pre and post 24/7/365 attending radiologist coverage support in an emergency department: fundamentals of data science

OBJECTIVE

To present a detailed exploratory data analysis for critically investigating the patterns in medical doctor (MD) to disposition time, pre and post 24/7/365 attending radiologist coverage, for patients presenting to an emergency department (ED).

MATERIALS AND METHODS

The process involved presenting several modeling techniques. To share an understanding of concepts and techniques, we used proportions, medians, and means, Mann-Whitney U test, Kaplan-Meier's (KM) survival analysis, linear and log-linear regression, log-ranked test, Cox proportional hazards model, Weibull parametric survival models and tertile analysis. Retrospective chart review was conducted to obtain a data set which was used to determine the trends in MD to disposition time. Data comprised of patients who had visited the emergency department (ED) during two distinct time periods and whose imaging studies were read by an attending emergency and trauma radiologist.

RESULTS

Median provided more insight into the data as compared with the mean. The Mann-Whitney U test was appropriate to evaluate MD to disposition time, but provided limited information. The Kaplan-Meier (KM) was able to offer more insight into the data since it did not assume an underlying model and that is the reason why it was appropriate. However, KM had limited ability to handle measured confounders and was unable to describe the magnitude of difference between curves. The Cox proportional hazards semi-parametric model or some other parametric model such as the Weibull could handle multiple measured confounders and described the magnitude of difference between two (survival) groups in the data set. However, both methods assumed underlying models that may not apply to the data set such as the one used in this study. Linear regression was unlikely to be appropriate due to the shape of survival time distributions, but log transforming the outcome could address the distribution issue. Nearly all the results of the KM subgroup analyses were consistent with the results of the log-transformed linear regression subgroup analyses and the interpretation of the results was the same for both.

CONCLUSION

Different statistical procedures may be applied to conduct exploratory subgroup analysis for a data set from a pre and post 24/7/365 attending coverage model. This could guide potential areas of further research to compare trends in MD to disposition time in ED. Pattern analysis provides evidence for various stakeholders to rethink the discourse about trends in MD to disposition time, pre and post 24/7/365 attending coverage. Graphical Illustration: The role of Emergency and Trauma Radiology in an Emergency Department.

Statistics 101 for Radiologists

Diagnostic tests have wide clinical applications, including screening, diagnosis, measuring treatment effect, and determining prognosis. Interpreting diagnostic test results requires an understanding of key statistical concepts used to evaluate test efficacy. This review explains descriptive statistics and discusses probability, including mutually exclusive and independent events and conditional probability. In the inferential statistics section, a statistical perspective on study design is provided, together with an explanation of how to select appropriate statistical tests. Key concepts in recruiting study samples are discussed, including representativeness and random sampling. Variable types are defined, including predictor, outcome, and covariate variables, and the relationship of these variables to one another. In the hypothesis testing section, we explain how to determine if observed differences between groups are likely to be due to chance. We explain type I and II errors, statistical significance, and study power, followed by an explanation of effect sizes and how confidence intervals can be used to generalize observed effect sizes to the larger population. Statistical tests are explained in four categories: t tests and analysis of variance, proportion analysis tests, nonparametric tests, and regression techniques. We discuss sensitivity, specificity, accuracy, receiver operating characteristic analysis, and likelihood ratios. Measures of reliability and agreement, including κ statistics, intraclass correlation coefficients, and Bland-Altman graphs and analysis, are introduced.

Normative bone mineral density z-scores for Canadians aged 16 to 24 years: the Canadian Multicenter Osteoporosis Study

The objectives of the study were to develop bone mineral density (BMD) reference norms and BMD Z-scores at various skeletal sites, to determine whether prior fracture and/or asthma were related to BMD, and to assess possible geographic variation of BMD among Canadian youth aged 16-24 yr. Z-Scores were defined as the number of standard deviations from the mean BMD of a healthy population of the same age, race, and sex. Z-Scores were calculated using the reference sample defined as Canadian Caucasian participants without asthma or prior fracture. Reference standards were created for lumbar spine (L1-L4), femoral neck, total hip, and greater trochanter, by each year of age (16-24 yr), and by sex. The Z-score norms were developed for groups noted earlier. Mean Z-scores between the asthma or fracture subgroups compared with the mean Z-scores in the reference sample were not different. There were minor differences in mean BMD across different Canadian geographic regions. This study provides age, sex, and skeletal site-specific Caucasian reference norms and formulae for the calculation of BMD Z-scores for Canadian youth aged 16-24 yr. This information will be valuable to help to identify individuals with clinically meaningful low BMD.

Health-related quality of life in Canadian adolescents and young adults: normative data using the SF-36

OBJECTIVES

Normative data for the SF-36 measure of health-related quality of life (HRQOL) exist for those over 25 years of age, based on data from the population-based Canadian Multicentre Osteoporosis Study (CaMos). CaMos recently recruited a sample of young Canadians aged between 16 and 24 years. The purpose of this study was to develop normative SF-36 data for this age group.

METHODS

After direct standardization to the Canadian population, means, standard deviations (SD), 95% confidence intervals and percentage at floor and ceiling were produced for the eight domain and two summary scores of the SF-36. Domains are scored from 0 (poor) to 100 (excellent). Summary scores are standardized to a mean of 50, with scores over 50 representing better than average and below 50 poorer than average function. Separate analyses were completed for men and women, and for those 16-19 years and 20-24 years.

RESULTS

The 1,001 community-based participants consisted of 474 men and 527 women from nine CaMos centres across Canada. Mean Physical Component Summary scores were 53.9 (SD = 6.9) and 53.3 (SD = 5.7) for young men and women, respectively. The equivalent Mental Component Summary scores were 49.3 (SD = 9.7) and 48.8 (SD = 8.9). In general, men scored somewhat higher than women, and younger (16-19 years) women scored higher than older (20-24 years) women, although the differences were small.

CONCLUSION

HRQOL is good in this cohort of young Canadians. Both men and women scored somewhat better on physically than mentally oriented domains. In general, Canadian scores were similar to those of the US, while a comparable Swedish sample scored higher than both countries on most domains. Results underscore the importance of taking country, age and gender into consideration when using normative data.