of histomorphologic diagnoses with special reference to the kappa statistic. APMIS 97: [689][690][691][692][693][694][695][696][697][698] 1989.Systems for classification and grading used in pathology should ideally be biologically meaningful and at least be reproducible from one pathologist to another. A statistical method to evaluate reproducibility (non-chance agreement) for several observers using nominal or ordinal categories has been developed and refined over the past few decadesthe kappa statistic. A high level of observed agreement among different pathologists can either signify a high level of reproducibility, if agreement by chance is low, or express a low level of reproducibility, if agreement by chance is almost as high as the observed agreement. Therefore, the observed agreement says nothing in itself, unless it is low. The kappa value, however, indicates how much better the observers are compared to a throw of the dice, and therefore gives the real credit to the agreement which was found. We have developed a user-friendly computer program for calculating inter-and intra-observer agreement of 2 or more observers. By calculating associations between different categories and different observers, the statistic furthermore obtains a function close to the parameter of accuracy. We recommend the use of the above method before a set of nominal or rank scale parameters are used for deciding prognosis and treatment of patients. By submitting a diskette the computer program will be available at no cost.
Objective. To evaluate the long-term mortality and renal outcome in a cohort of Danish patients with lupus nephritis (LN) and to identify outcome predictors among findings registered at the time of the first renal biopsy. Methods. The cohort consisted of 100 patients diagnosed with LN (World Health Organization classes I-VI) between 1971 and 1995 and followed for a median duration of 14.7 years (range 0.01-36.9 years). Standardized mortality ratios (SMRs) were calculated on the basis of national age-, sex-, and calendar-year period-specific death rates. Results. Thirty-seven deaths occurred in the cohort, corresponding to an overall SMR of 6.8 (95% confidence interval [95% CI] 4.9 -9.4). Excess mortality was observed throughout followup. The SMR estimates were 9.0 (95% CI 4.7-17.1), 6.2 (95% CI 4.0 -9.5), and 6.6 (95% CI 3.1-13.8) for patients diagnosed during the calendar-year periods 1971-1979, 1980 -1989, and 1990 -1995, respectively. The cumulative renal survival after 5, 10, and 20 years of followup was 87%, 83%, and 73%, respectively. The risk of end-stage renal disease (ESRD) did not decrease significantly across calendaryear periods. Systolic blood pressure >180 mm Hg, focal segmental nephritis, and advanced sclerosing nephritis were identified as baseline predictors of death in multivariate regression analyses, while systolic blood pressure >180 mm Hg, serum creatinine level >140 moles/liter, and diagnostic delay predicted progression to ESRD. Conclusion. LN is associated with excess long-term mortality, and patients may progress to ESRD even after prolonged followup. Our analyses indicate that focal segmental histopathology at disease onset constitutes an important risk factor for death among LN patients. Moreover, our data underscore the importance of early intervention, blood pressure control, and long-term followup in LN.
LN is associated with markedly increased morbidity from IHD. Our findings indicate that patients with early-onset LN have a disturbingly high risk of IHD compared to the general population.
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