NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

Santaguida PL, Balion C, Hunt D, et al. Diagnosis, Prognosis, and Treatment of Impaired Glucose Tolerance and Impaired Fasting Glucose. Rockville (MD): Agency for Healthcare Research and Quality (US); 2005 Sep. (Evidence Reports/Technology Assessments, No. 128.)

**This publication is provided for historical reference only and the information may be out of date.**

## Diagnosis, Prognosis, and Treatment of Impaired Glucose Tolerance and Impaired Fasting Glucose.

Show details
**
Section A:
**

**Calculation of kappa coefficient and confidence intervals (CI)**

The simple kappa coefficient is calculated as:

where

andThe Variance and CI are calculated as follows:

where

and

**
Section B:
**

**Calculation of annualized relative risk, annualized risk for the exposed (IFG or IGT) and the normal glucose groups**

Calculation of relative risk (*RR _{ t}*) at time

*t*would be as follows:

where

= Calculated Risk in Exposed Group at time t (or i.e. in Male) and calculated as:

= Calculated Risk in Control Group at time t (or i.e. in Female)

and can be calculated as:

is Observed Risk after T period in Exposed Group

is Observed Risk after T period in Control Group

thus

where

*T*= Observed duration of study (0.5 to 18 years).

*t*= Up to one year study duration.

**
Section C:
**

**Calculation of 95% confidence intervals (CI) for the unadjusted annualized RR**

Where:

**
Section D:
**

**Calculation and test of heterogeneity (Q) and the pooled estimate of RR{36574}:**

Where k is the number of studies being combined, *RR _{ i}* is
the relative risk estimate in i

^{th}Study,

is the weighted estimator of relative risk, and *W _{ i}* is
the weight attached to that study (the reciprocal of the variance of the
i

^{th}study, var

*RR*).

_{ i}
*Q* is approximately distributed as a *X*
^{2} distribution with *k*- 1 degrees of freedom under
*H _{ 0}*

Fixed effects model

Random effect model

and

Further, define

**The estimated component of variance due to inter-study variation in effect
size,, is calculated as:**

and

Adjusted weights for each of the studies is calculated as

**The mean relative risk estimate of all studies can then be computed by:**

**The variance of this estimate is calculated as:**

**U.S. Department of Health and Human Services**

Mike Leavitt,* Secretary*

**Office of Public Health and Science**

Richard H. Carmona, M.D., M.P.H., F.A.C.S.,* Surgeon General of the United
States*

**Agency for Healthcare Research and Quality**

Carolyn M. Clancy, M.D.,* Director*

- Appendix G. Calculations - Diagnosis, Prognosis, and Treatment of Impaired Gluco...Appendix G. Calculations - Diagnosis, Prognosis, and Treatment of Impaired Glucose Tolerance and Impaired Fasting Glucose

Your browsing activity is empty.

Activity recording is turned off.

See more...