Severity assessment of ADRs: The term severity is often used to describe the intensity of a medical event, as in grading ‘mild’, ‘moderate’ and ‘severe’. Severity assessment categorizes the ADRs as mild, moderate, or severe based on the based on the steps taken for the management of the ADRs.
Karch and Lasagna classified severity into minor, moderate, severe and lethal as defined below:
i. Minor: no antidote, therapy or prolongation of hospitalization required.
ii. Moderate: requires a change in drug therapy, specific treatment or an increase in hospitalization by at least 1 day.
iii. Severe: potentially life threatening, causing permanent damage or requiring intensive medical care.
iv. Lethal: directly or indirectly contributes to the death of the patient.
The USFDA classifies an ADR as serious when it results in death, life- threatening causes, or prolongs hospitalization, causes a significant persistent disability, results in a congenital anomaly, or requires intervention to prevent permanent damage.
Hartwig et al categorized ADRs into seven levels as per their severity. Level 1 & 2 fall under mild category, level 3 & 4 under moderate and level 5, 6 & 7 fall under category severe. (See below)
ADR severity assessment scale
(Modified Hartwig and Siegel)
Level 1: The ADR requires no change in treatment with the suspected drug.
Level 2: The ADR requires that the suspected drug be withheld, discontinued or otherwise changed. No antidote or other treatment is required, and there is no increase in lenght of stay.
Level 3: The ADR requires that the suspected drug be withheld, discontinued or otherwise changed, and/ or an antidote or other treatment is required. There is no increase in lenght of stay.
Level 4 (a): Any level 3 ADR that increases lenght of stay by at least one day.
Level 4 (b): The ADR is the reason for admission.
Level 5: Any level 4 ADR that requires intensive medical care.
Level 6: The ADR causes parmanent harm to the patient.