Litovitz and Manoguerra used the hazard factor (HF) to compare drugs or chemicals associated with adverse reactions. The HF allows comparison of relative risk between different hazards. The authors are from Georgetown University and the University of California San Diego.
Parameters:
(1) major adverse effects, nonfatal
(2) fatalities
(3) total number of exposures to the substance
(4) number of major adverse effects and deaths for all exposures to all drugs and chemicals in a poison control database (for the San Diego Poison Control Center this 0.0006208)
hazard ratio = HR =
= (((major adverse effects) + (deaths)) / (total number of exposures)) / (data for all exposures of all drugs)
Interpretation:
• A drug with "average" risk would have a hazard ratio of 1.0.
• The higher the hazard ratio the greater the risk of an adverse drug effect.
• The lower the hazard ratio the lower the risk.
Limitations:
• This requires that all significant events be reported.
• There may be inter-observer variation for a major adverse effect.
• Data on total exposures needs to be accurate.
• Since this is a ratio and since many drugs would face the same problems in data accuracy there may be some cancelling out of error.
