Horn et al developed a Patient Severity Index (PSI) that can be used for preparing case mix groups of hospitalized patients. The authors are from the Johns Hopkins University in Baltimore.
Parameters:
(1) stage of principal diagnosis (chief complaint)
(2) interactions (concurrent or comorbid conditions)
(3) response to therapy, rate of
(4) response to therapy, residual findings after therapy
(5) complications
(6) dependence on hospital facilities and staff (disability, requirements for equipment, etc.)
(7) extent of procedures not performed in the operating room
|
Parameter |
Finding |
Points |
|---|---|---|
|
principal diagnosis |
asymptomatic |
1 |
|
|
moderate manifestations |
2 |
|
|
major manifestations |
3 |
|
|
catastrophic |
4 |
|
interacting conditions |
none |
1 |
|
|
low |
2 |
|
|
moderate |
3 |
|
|
major |
4 |
|
rate of response to therapy |
prompt |
1 |
|
|
moderate delay |
2 |
|
|
serious delay |
3 |
|
|
no response |
4 |
|
residual findings after therapy |
none |
1 |
|
|
minor |
2 |
|
|
moderate |
3 |
|
|
major |
4 |
|
complications |
none or very minor |
1 |
|
|
moderate |
2 |
|
|
major |
3 |
|
|
catastrophic |
4 |
|
dependence |
low |
1 |
|
|
moderate |
2 |
|
|
major |
3 |
|
|
extreme |
4 |
|
extent of non-OR procedures |
noninvasive diagnostic |
1 |
|
|
therapeutic or invasive diagnostic |
2 |
|
|
nonemergency life-sustaining |
3 |
|
|
emergency life-sustaining (critical care) |
4 |
where:
• A major complications is one that is as important or more important than the principal diagnosis.
• The appendix to the paper provides definitions for all of the parameters.
severity index =
= SUM(points for all 7 parameters)
Interpretation:
• minimum score: 7
• maximum score: 28
• The higher the score the more severe the patient's condition.
percent of maximal score =
= (((patient severity index) – 7) / 21) * 100%
Limitations:
• This would probably work fairly well for many simple situations but might start to decompensate with really complex clinical problems with many principal diagnoses.
Purpose: To evaluate the severity of a patient's illness using the Patient Severity Index of Horn et al.
Objective: severity, prognosis, stage, disease progression, economic cost
ICD-10: Z51.9,
