Lecture 16- Biostatistics and Data in Public Health and Lecture 17- Epidemiology of Vision Loss

Published Examination-based Prevalence of Major Eye Disorders

Bonnielin Swenor; details the findings of a literature review on the prevalence of vision loss and major eye disorders

Prevalence of AMD varies from

1.1% to 40.5%

NHANEs showed what about prevalence of AMD

varies with age and race/ethnicity

Prevalence of diabetic retinopathy varies from

1.2% to 48%

Prevalence of open-angle glaucoma varies from

1.9% to 13.8%

Prevalence of uncorrected refractive error varies from

1.8% to 15.1%

Prevalence of cataract varies from

2.8% to 29.5%

Prevalence of vision impairment overall varies from

0.7% to 7.5%

Null hypothesis

the hypothesis that there is no significant difference between specified populations, any observed difference being due to sampling or experimental error.

Alternative Hypothesis

The hypothesis that there is a relationship between the dependent and independent variables; accepted when null is rejected

Statistical Significance

how likely it is that an obtained result occurred by chance

Type 1 Error

Rejecting null hypothesis when it is true; declared statistically significant different when none existed (false positive)

Type 2 Error

failing to reject a false null hypothesis; declared to be. no statistically significant different when a different exists (false negative)

Internal validity

measurements accurately reflect the sample (make a gold standard)

External validity

extent to which we can generalize findings to real-world settings; measurements accurately reflect the sample population

Generalizability

the extent to which we can claim our findings inform us about a group larger than the one we studied

Selection Bias

in an experiment, unintended differences between the participants in different groups; subjects may not be representative of the target population

Information Bias

can be introduced as a result of measurement error or misclassification; accuracy is impacted; recall bias

Recall bias

People may not know or can't accurately recount a disease or a problem

Interviewer Bias

effects of interviewers on respondents that lead to biased answers; way the questions are asked

Confounding Bias

Groups being tested for differences have some underlying difference which is not controlled and could b the reason for the end result.

Two studies that are even better than Randomized Trials

Systematic Review and Meta-Analysis

Big Data

Data that is too large and complex that it exceeds the storage or computing capacity of most systems ability to perform timely and accurate analysis

Data sources

collections of information; emphasis on administrate data and clinical registries

Data integration

bringing together data from 2 or more sources linking the same person or event together

Systematic Review

summarized findings from multiple studies of a specific clinical practice question or topic that recommend practice changes and future directions for research; one of the strongest sources of evidence for evidence-based practice

Meta-analysis

statistical analysis of a large collection of analysis results from individual studies for the purpose of integrating the findings

Cochrane Collaboration

an international organization that aims to facilitate well-informed decisions about health care by preparing systematic reviews of the effects of health care interventions

Variable

any characteristic that differs from person to person

Nominal/categorical variable

categories do not have a natural order/numerical ranking

Ordinal variable

a qualitative variable that incorporates an ordered position, or ranking but the spacing may not be even

Interval variable

a variable used for observations that have numbers as their values; the distance (or interval) between pairs of consecutive numbers is assumed to be equal but there is no true zero point

Ratio variable

a variable that meets the criteria for an interval variable but also has a meaningful zero point

Qualitative/categorical variables

nominal or ordinal

Quantitative/Continuous variables

interval and ratio