Concept: Morbidity Classification System in Children

1 - Conceptual Framework

Based on classifications system of childhood morbidity, a construct was developed to describe health care utilization in children (Newacheck and Starfield 1988; Starfield et al 1985; Starfield et al 1984) . Health care contacts are categorized according to the reason for health care, as follows:


1. acute conditions,
   
2. recurrent conditions,
   
3. permanent conditions,
   
4. perinatal conditions and
   
5. preventative care.

The classification system is a "non-categorical" approach to defining illness in children that describes elements shared by conditions, such as impact on the child's functional status or need for medical services (Newacheck and Starfield 1985; Stein et al 1993; Perrin et al 1993). This perspective enables the assessment of the burden of illness on the health care system, and of the impact of illness on the child in terms of the inconvenience and discomfort of continuous therapeutic management and contact with the health care system (Perrin et al 1993).

Acute conditions are self-limiting conditions, or conditions which regress after treatment; they appear as single, isolated episodes of health care.

Permanent conditions are conditions, either congenital or acquired, which would likely persist throughout childhood and/or require continuous health care, such as dependence on medications, special diet, medical technology or devices and personal assistance (Stein et al 1993).

Recurrent conditions are conditions that result in repeated, though not necessarily regular, contact with the health care system over a 1 year period. The concept of recurrence was used to identify conditions which would potentially impact on a child's everyday activities (Perrin et al 1993).

Perinatal conditions occur only in the newborn period.

Visits for preventative care include health care contacts for routine examinations and vaccinations.

This system was developed for a project by Kozyrskyj et al. (2001) prior to the John Hopkin's ACG system, which we now recommend in its place.

2 - Operational Definitions

The classification of ICD-9 diagnosis codes into : 1) acute conditions, 2) recurrent conditions, 3) permanent conditions, 4) perinatal conditions and 5) preventative care is described in Table 1 . The operational definitions for permanent and recurrent conditions are described in further detail as follows:


• Permanent condition
  
  A single physician or hospital contact (primary diagnosis only) for any 3-digit ICD-9 diagnosis code that appears in the permanent condition category, listed in Table 1A, denotes a child with a permanent condition with the following exceptions:
  
  
  1. children with AIDS are identified by the 5-digit ICD-9 diagnosis code of "0795" in any of the 16 diagnosis codes in the hospital record.
     
     
  2. asthma is categorized as a permanent condition if there were at least two health care contacts for the 3-digit ICD-9 diagnosis of "493".
     
     
  3. children with congenital malformations are identified from a review of listed 3-digit diagnoses from time of birth to 2 years of age.
  
  
• Recurrent condition
  
  A single ambulatory or hospital contact (primary diagnosis only) for any 3-digit ICD-9 diagnosis code that appears in the recurrent condition category* listed in Table 1B denotes a child with a recurrent condition if any of the following conditions are met:
  
  
  1. presence of ambulatory visits, or hospital visits with LOS <=7 days, over 2 or more consecutive quarter time periods in one year.
     
     
  2. presence of ambulatory visits, or hospital visits with LOS <=7 days, over 3 non-consecutive quarter time periods in one year.
     
     
  3. occurrence of ambulatory, or hospital visits with LOS <= 7 days, in single quarter time periods only if there are no more than 3 visits in the quarter.
     
     
  4. any occurrence of a hospital visit for > 7 days.
  
  
  Note * - add acute condition category to completely enumerate all children with recurrent conditions.

Table 1. ICD-9 Diagnosis Classification System for Childhood Conditions

Classification ICD-9-CM Diagnosis Code

A. Permanent conditions


AIDS [incl. HIV positive] * 042, V08, 0795
Arthropathies (excl. infectious, joint pain) * 710, 712-718
720-723, 725-728, 731-39, V49
Asthma * 493
Cardiac disease * 392-454, 456-458
Cerebral palsy and other paralyses 342-344
CNS disorders (excl. epilepsy, paralyses) 324-341, 347-349
V48
Congenital anomalies (excl. spina bifida) 740, 742-59, 771
Cystic fibrosis and other * 277
Diabetes Mellitus * 250
Endocrine, other than diabetes 252-259
Epilepsy * 345
Gastroenteritis, colitis & malabsorption * 555-7, 579,V44
Hematologic (sickle cell, excl, anemia) * 281-289
Mental Retardation 317-319
Metabolic/immune disorders * 270-3, 279
Neoplasms * 140-215, 217-239, V10
Neuromuscular disorders (incl. polio) 350-359, 045-049,138
Ophthalmic disorders (excl. conjuctivitis) 360-71, 374-9,V41
Dental diseases 520-522, 524-526
Otic disorders (excl. otitis media) 383-387, 389
Renal failure * 582-589
Spina bifida * 741
Thyroid disease * 240-246
Miscellaneous V12, V13, V15, V42, V43, V45-V47

Note: * - conditions which require chronic use of medications/devices

B. Conditions Likely to Recur: ICD-9-CM Diagnosis Code


Anemia 280
Benign tumour 216
Conjuctivitis/blepharitis 372-373
COPD (eg. bronchitis) 490-2,494-6
Gastroenteritis (noninfectious diarrhea) 558
Gastrointestinal ulcer and diseases 530-537
Gastrointestinal disease, other (eg.constipation)560-569
Hepatic/pancreatic disease 570-577
Hernia 550-553
Joint pain 719, 724, 729
Migraines and headaches 346,784
Nephritis/nephrosis 580, 581
Neurotic disorders (eg. enuresis, ADD) 300-316, V11,V40
Otitis media 380-382
Pregnancy diseases (incl. birth) 630-676, V22-V24, V27, V28
Psychotic disorders (autism) 290-299
Renal disease (eg. pyelonephritis, UTI) 590-599
Reproductive organ disorders 600-629
Respiratory disease, chronic (allergies) 470-478
Respiratory disease, other 500-519
Skin diseases (psoriasis) 690-698
Social problems V60-V62
Tuberculosis 010-018, 137
Under-nutrition/Obesity 783, 278, 260-269

C. Acute Self-limiting Conditions


Appendicitis 540-543
Ear symptoms 388
Electrolyte disorders 274-276, 251
Helminthiases 120-129
Hemorrhage (incl. GI, other) 578, 459
Hemorrhoids 455
Ill-defined symptoms (excl. 783) 780-799
Infectious/Parasitic diseases 001-9, 020-041, 080-088, 100-104, 130-6
Injuries 800-999
Meningitis 320-323
Mouth disorders 523, 527-529
Mycoses 110-118
Pneumonia and influenza 480-487
Procedures V50-V59, V63, V64, V66-V68
Respiratory infections 460-466
Rheumatic fever, acute 390-391
Skin diseases, other (eg. rashes) 700-709
Skin infections 680-686
Venereal diseases 090-099
Viral diseases (eg. chickenpox, mumps) 050-7, 060-066, 070-079, 139

D. Perinatal Conditions (incl. birth)


760-779, V29-V39

E. Preventative Care


Immunizations V01-V07
Preventative, other V25, V26, V65, V69, V71-V82
Routine Examinations V20, V21, V70
Optometrist Examinations mdbloc=053

3 - SAS Program Code

The program code categorizes ICD-9 diagnoses into: 1) acute conditions,2) recurrent conditions, 3) permanent conditions, 4) perinatal conditions and 5) visits for preventative care, as outlined in Table 1.


• Note : Visits to the optometrist (mdbloc=053) were classified as visits for preventative care in another program.

The operational definition of a recurrent condition was applied to the Table 1 list of ICD-9 diagnoses, as detailed in the program code (YYY). The basis steps in the program are as follows:


1. division of fiscal year into quarter time periods and classification of a health care contact by its occurrence in a quarter time period (i.e.: 1,2,3,4).
   
   
2. children with any occurrence of a hospitalization of > 7 days are classified with recurrent illness.
   
   
3. of children with physician visits and short hospital stays (< 7days), those with at least 3 visits over 3 months (1 quarter) are defined as those with recurrent illness.
   
   
4. for children excluded in ii) and iii), the presence of recurrent disease is determined if the sum of the label for the quarter time period for health care contact follows the patterns described in Table 2.
   
   Table 2. Operational Definition of a Recurrent Condition in a Child
   

   1st quarter = Apr,May,Jun;
   2nd quarter = Jul,Aug,Sep;
   3rd quarter = Oct,Nov,Dec;
   4th quarter = Jan,Feb,Mar.
   
   Quarter Time Periods Sum of Quarters* Pattern of Recurrence

   Recurrence in children with visits in 4th quarter if:
   4,3,2,1 10 4/4
   4,3,2 9 ¾ consecutive
   4,3,1 8 ¾ non-consecutive
   4,2,1 7 ¾ non-consecutive
   4,3 7 2/4 consecutive
   
   Non recurrent if:
   4,2 6 2/4 non-consecutive
   4,1 5 2/4 non-consecutive
   
   Recurrence in children with visits in 2nd and 3rd quarters if:
   3,2,1 6 3/3
   3,2 5 2/3 consecutive
   2,1 3 2/3 consecutive
   
   Non recurrent if:
   3,1 4 2/3 non-consecutive

   Note; * - quarter periods were summed to identify different patterns of recurrence; children were grouped by visits in the 2nd/3rd versus 4th quarter in order to differentiate sums of quarters which were the same but indicated different patterns of recurrence.