Table 2.
TP and FP heat-related ED visits identified by non–heat syndrome case definition keywords and heat-related ICD-9-CM codes,a by identification method, for all civilian hospital-affiliated EDs in North Carolina, January 1, 2012, to December 31, 2014b,c
| Visits by Identification Method, No. (%) | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ICD-9-CM Code Only | Current Keyword Onlyd | ICD-9-CM Code + Current Keyword | Additional Keyword Onlyd | ICD-9-CM Code + Additional Keyword | |||||||||||
| Keyword | Total | TP | FP | Total | TP | FP | Total | TP | FP | Total | TP | FP | Total | TP | FP |
| Reviewed ED visits | 222 | 70 (32) | 14 (6) | 249 | 39 (16) | 200 (80) | 55 | 37 (67) | 2 (4) | 18 | 9 (50) | 2 (11) | 15 | 5 (33) | 0 (0) |
| Burne | 19 | 2 (11) | 3 (16) | 121 | 1 (1) | 120 (99) | 2 | 2 (100) | 0 (0) | 5 | 0 (0) | 2 (40) | 1 | 0 (0) | 0 (0) |
| Radiator or antifreeze | 0 | NA | NA | 10 | 0 (0) | 10 (100) | 0 | NA | NA | 0 | NA | NA | 0 | NA | NA |
| Grease, liquid, or oil | 4 | 0 (0) | 3 (75) | 131 | 1 (1) | 129 (98) | 0 | NA | NA | 1 | 0 (0) | 0 (0) | 0 | NA | NA |
| Shower | 10 | 4 (40) | 4 (40) | 15 | 3 (20) | 8 (53) | 1 | 0 (0) | 1 (100) | 1 | 1 (100) | 0 (0) | 0 | NA | NA |
| Water | 65 | 63 (97) | 0 (0) | 83 | 27 (33) | 51 (61) | 26 | 26 (100) | 0 (0) | 10 | 7 (70) | 0 (0) | 4 | 4 (100) | 0 (0) |
| Smoke inhalation | 2 | 0 (0) | 0 (0) | 106 | 0 (0) | 105 (99) | 1 | 1 (100) | 0 (0) | 0 | NA | NA | 0 | NA | NA |
| Fire | 11 | 1 (9) | 0 (0) | 17 | 7 (41) | 9 (53) | 10 | 10 (100) | 0 (0) | 3 | 2 (67) | 1 (33) | 1 | 1 (100) | 0 (0) |
| Heater | 1 | 0 (0) | 0 (0) | 13 | 1 (8) | 12 (92) | 0 | NA | NA | 0 | NA | NA | 0 | NA | NA |
| Hot tub, sauna, or hot spring | 6 | 0 (0) | 6 (100) | 2 | 0 (0) | 2 (100) | 1 | 0 (0) | 1 (100) | 0 | NA | NA | 0 | NA | NA |
| E900.1f | 114 | 0 (0) | 4 (4) | 0 | NA | NA | 18 | 0 (0) | 2 (11) | 0 | NA | NA | 9 | 0 (0) | 0 (0) |
Abbreviations: ED, emergency department; FP, false positive; ICD-9-CM, International Classification of Diseases, Ninth Revision, Clinical Modification; NA, not applicable; TP, true positive.
aHeat-related ICD-9-CM codes included 992, 992.0-992.9, E900, E900.0, E900.1, E900.9.7
bColumn numbers are mutually exclusive. If a record was not categorized as a TP or FP, it was unclassifiable (column not shown). Row numbers are not mutually exclusive. Stratified results by keyword or diagnosis do not sum to the total number of ED visits because of overlapping categories.
cData source: unpublished data, North Carolina Disease Event Tracking and Epidemiologic Collection Tool (NC DETECT).
d Current refers to keywords included in the heat syndrome case definition at the time of the study. Additional refers to keywords evaluated during the process of refining the heat syndrome definition. These keywords were not included in the current heat syndrome definition.
eIncludes “BURN,” “burn,” “Burn,” “burn(s),” “Burn(s),” “BURN(s),” “BURNS,” “burns,” “Burns,” “(BURN),” “(burn),” or an ICD-9-CM code of 940.0-949.9. ED visits with burn keyword, n = 53; ED visits with burn diagnosis code, n = 60; ED visits with both, n = 35.
fThe ED visits in this category were identified by the ICD-9-CM code E900.1 in the E-code fields and not by keywords in the chief complaint/triage note fields.