A revision to the United States national ALS registry’s algorithm to improve Case-Ascertainment

Abstract

Objective

To evaluate the impact of 1) updating the existing algorithm to improve case-finding sensitivity and 2) reclassifying the Registry’s diagnostic status nomenclature into four new categories (“confirmed ALS,” “likely ALS,” “undetermined ALS,” or “not ALS”) versus the current three (“definite ALS,” “possible ALS,” or “not ALS”) to be more inclusive and descriptive of cases and individuals.

Methods

A retrospective analysis of Registry data from 2011–2017 was conducted to follow “possible ALS” individuals over time to determine what qualifier caused them to convert, if at all and when, to Registry-eligible cases (i.e. “confirmed ALS” or “likely ALS”).

Results

In 2011, 720 individuals were classified by the Registry algorithm as having “possible ALS”. By 2017, 42% of these had converted to Registry-eligible ALS cases. Approximately 14% of those who were identified solely based on an ALS prescription drug never converted to Registry-eligible cases. This analysis indicates that “possible ALS” individuals with a single prescription for an ALS drug should be converted to Registry-eligible cases which would add between 300–500 cases per year on average.

Conclusions

The Registry’s existing algorithm likely results in the under-ascertainment of ALS cases. However, updating the algorithm with the inclusion of patients having been prescribed ALS-specific drugs, even with a single prescription, leads to improved epidemiologic estimates of ALS in the US. This and future algorithmic updates will help the Registry more accurately depict the true disease burden of ALS in the US.

Keywords:

• Amyotrophic lateral sclerosis
• registry
• case-ascertainment
• United States

Acknowledgements

The authors are grateful to those living with ALS who give their valuable time to contribute important health data to researchers. Without their help, these findings, and countless others, would not be possible.

Disclaimer

The findings and conclusions in this report are those of the authors and do not necessarily represent the official positions of the Agency for Toxic Substances and Disease Registry, the Centers for Disease Control and Prevention, and/or the US Department of HHS.

Declaration of interest

The CDC/ATSDR authors have no declarations of interest. Dr. Berry, Dr. Brooks, Dr. Oskarsson, and Dr. Goutman have no declarations of interest linked to the study.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by the Centers for Disease Control and Prevention (CDC)/Agency for Toxic Substances and Disease Registry (ATSDR). The findings and conclusions in this report are those of the authors and do not necessarily represent the views of CDC/ATSDR.