For decades one of our most relied upon metrics for gauging the severity of our yearly flu seasons has been the 122 Cities Mortality Reporting System (122 CMRS), although it is not without some serious limitations.
Deaths are normally counted whenever `influenza' or `pneumonia' are listed anywhere on the death certificate, although some sites only report if they are listed as `underlying causes of death'.
Adding to this inconsistency, deaths are reported for the week the death certificate was filed, not the date of death. And the 122 cities included in this report only cover about 25% of the country.
A more precise measurement is reported by the National Center for Health Statistics (NCHS) mortality surveillance data, which collects death certificate data for all deaths in the United States. But until relatively recently the lag time for gathering and collating that data was measured in months and even years.
But with recent advances in Electronic Death Registration (EDR) systems, the lag in assembling this data has dropped dramatically.
Beginning with the 2014-2015 influenza season, the CDC's Influenza Division and the National Center for Health Statistics (NCHS) collaborated on a pilot project to use NCHS mortality surveillance data on pneumonia and influenza (P&I) mortality.
For the past year, the NCHS data and the 122CMRS have both appeared in the weekly FluView report, but starting next week, the NCHS P&I mortality chart will appear alone, as the 122CMRS is retired.
This notice from Thursday's MMWR:
Notice to Readers: Update to Reporting of Pneumonia and Influenza Mortality
Weekly / October 7, 2016 / 65(39);1088
The current issue of MMWR (week 39) will be the last to include data from the 122 Cities Mortality Reporting System (122 CMRS) in Notifiable Disease and Mortality Tables, Table III (“Deaths in 122 cities” [http://www.cdc.gov/mmwr/volumes/65/wr/mm6539md.htm?s_cid=mm6539md_w#table-17]).
Beginning in the publication for the week ending October 8, 2016 (week 40), data from the National Center for Health Statistics (NCHS) Mortality Surveillance System will replace the information reported in Table III, and the 122 Cities Mortality Reporting System (122 CMRS) will be retired.
The NCHS Mortality Surveillance System provides improvements in the data, including reports by the week of death and a consistent pneumonia and influenza (P&I) case definition across all sites. These improvements, along with recent and continuing increases in the timeliness of death certificate data, have led CDC to update the P&I mortality surveillance platform from the 122 CMRS to the NCHS Mortality Surveillance System.
NCHS collects death certificate data from state vital statistics offices for virtually all deaths occurring in the United States. P&I deaths are identified based on International Classification of Disease, Tenth Revision multiple cause of death codes. The NCHS Mortality Surveillance System data will be presented by the week the death occurred. The percentage of deaths attributed to P&I on a national level will be released 2 weeks after the week of death to allow for collection of enough data to produce a stable percentage.
Table III will present NCHS Mortality Surveillance System data by state and region with the 2-week lag, and areas with less than 20% of the expected total deaths will be marked as insufficient data.
However, collection of complete data is not expected at the time of initial report, and the level of completeness will not likely be sufficient to calculate a reliable percentage of deaths attributed to P&I at the U.S. Department of Health and Human Services region* or state level within this 2-week period. The data for earlier weeks are continually revised, and the proportion of deaths attributed to P&I might increase or decrease as new and updated death certificate data are received by NCHS. The most recent data can be found online (https://data.cdc.gov), and historical data from both NCHS and 122 CMRS also will be available at that site.
* The 10 U.S. Department of Health and Human Services regions consist of the following jurisdictions. Region 1: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont; Region 2: New Jersey, New York, and New York City; Region 3: Delaware, District of Columbia, Maryland, Pennsylvania, Virginia, and West Virginia; Region 4: Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, and Tennessee; Region 5: Illinois, Indiana, Michigan, Minnesota, Ohio, and Wisconsin; Region 6: Arkansas, Louisiana, New Mexico, Oklahoma, and Texas; Region 7: Iowa, Kansas, Missouri, and Nebraska; Region 8: Colorado, Montana, North Dakota, South Dakota, Utah, and Wyoming; Region 9: Arizona, California, Hawaii, and Nevada; Region 10: Alaska, Idaho, Oregon, and Washington.