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Multicenter Study
. 2021 Apr;34(2):325-335.
doi: 10.1007/s40620-020-00946-3. Epub 2021 Jan 2.

Risk factors and action thresholds for the novel coronavirus pandemic. Insights from the Italian Society of Nephrology COVID-19 Survey

Maurizio Nordio #  1 , Gianpaolo Reboldi #  2 , Anteo Di Napoli #  3 , Giuseppe Quintaliani  4 , Federico Alberici  5 , Maurizio Postorino  6 , Filippo Aucella  7 , Piergiorgio Messa  8 , Giuliano Brunori  9   10 ; Italian Society of Nephrology COVID-19 Research Group
Collaborators, Affiliations
Multicenter Study

Risk factors and action thresholds for the novel coronavirus pandemic. Insights from the Italian Society of Nephrology COVID-19 Survey

Maurizio Nordio et al. J Nephrol. 2021 Apr.

Abstract

Background and aim: Over 80% (365/454) of the nation's centers participated in the Italian Society of Nephrology COVID-19 Survey. Out of 60,441 surveyed patients, 1368 were infected as of April 23rd, 2020. However, center-specific proportions showed substantial heterogeneity. We therefore undertook new analyses to identify explanatory factors, contextual effects, and decision rules for infection containment.

Methods: We investigated fixed factors and contextual effects by multilevel modeling. Classification and Regression Tree (CART) analysis was used to develop decision rules.

Results: Increased positivity among hemodialysis patients was predicted by center location [incidence rate ratio (IRR) 1.34, 95% confidence interval (CI) 1.20-1.51], positive healthcare workers (IRR 1.09, 95% CI 1.02-1.17), test-all policy (IRR 5.94, 95% CI 3.36-10.45), and infected proportion in the general population (IRR 1.002, 95% CI 1.001-1.003) (all p < 0.01). Conversely, lockdown duration exerted a protective effect (IRR 0.95, 95% CI 0.94-0.98) (p < 0.01). The province-contextual effects accounted for 10% of the total variability. Predictive factors for peritoneal dialysis and transplant cases were center location and infected proportion in the general population. Using recursive partitioning, we identified decision thresholds at general population incidence ≥ 229 per 100,000 and at ≥ 3 positive healthcare workers.

Conclusions: Beyond fixed risk factors, shared with the general population, the increased and heterogeneous proportion of positive patients is related to the center's testing policy, the number of positive patients and healthcare workers, and to contextual effects at the province level. Nephrology centers may adopt simple decision rules to strengthen containment measures timely.

Keywords: COVID-19; Classification tree; Contextual analysis; Renal replacement therapy.

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Conflict of interest statement

On behalf of all authors, the corresponding author states that there is no conflict of interest.

Figures

Fig. 1
Fig. 1
Predicted post-estimation counts with 95% confidence intervals by province and ranked from the lowest to the highest. Although the variability is high, only three provinces are significantly different from zero
Fig. 2
Fig. 2
Predicted post-estimation count due to the general contextual effect at the province level. A negative value indicates that the contextual effect reduces the expected count, a near null value indicates that the contextual effect is negligible, a positive value suggests an increase in the expected count due to the contextual effect
Fig. 3
Fig. 3
The decision tree shows the rules and split points to estimate the number of SARS-CoV-2 positive patients. The first row in each box shows the estimated number of cases, the second row the number of patients and the number of centers, the third row the percentage of cases covered
See this image and copyright information in PMC

References

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