How to Calculate PQI #2: Perforated Appendix Admission Rate

A perforated appendix is one of the complications of acute appendicitis. If appendicitis is left untreated, ischemic necrosis of a portion of appendiceal wall may occur, leading to perforation. An appendicolith is thought to be associated with a higher probability of perforation. Perforation of the appendix is more common among the elderly population due to an increased frequency of late and atypical presentation of appendicitis, delay in diagnosis, delayed decision for surgery and to the age-specific physiological changes.

Population Measured (Denominator)
Discharges, for patients ages 18 years and older, with any-listed ICD-CM diagnosis codes for appendicitis. Discharges are assigned to the denominator based on the metropolitan area or county of the patient residence, not the metropolitan area or county of the hospital where the discharge occurred.

ICD-9-CM    Description
540.0    Acute appendicitis with generalized peritonitis
540.1    Acute appendicitis with peritoneal abscess
540.9    Acute appendicitis without mention of peritonitis
541    Appendicitis, unqualified
ICD-10-CM    Description
K35.2    Acute appendicitis with generalized peritonitis
K35.3    Acute appendicitis with localized peritonitis
K35.80    Unspecified acute appendicitis
K35.89    Other acute appendicitis
K37.    Unspecified appendicitis

NUMERATOR:
Discharges, among cases meeting the inclusion and exclusion rules for the denominator, with any-listed ICD-CM diagnosis codes for perforations or abscesses of appendix. 
ICD-9-CM    Description
540.0    Acute appendicitis with generalized peritonitis
540.1    Acute appendicitis with peritoneal abscess
ICD-10-CM    Description
K35.2    Acute appendicitis with generalized peritonitis
K35.3    Acute appendicitis with localized peritonitis

Exclude cases:
•transfer from a hospital (different facility)
•transfer from a Skilled Nursing Facility (SNF) or Intermediate Care Facility (ICF)
•transfer from another health care facility
•MDC 14 (pregnancy, childbirth, and puerperium) 
•with missing gender (SEX=missing), age (AGE=missing), quarter (DQTR=missing), year (YEAR=missing), principal diagnosis (DX1=missing), or county (PSTCO=missing)