Drugs and Aging

Approximately 10–16 percent of hospital admissions result from adverse drug reactions from which approximately two-thirds of patients recover (Colt and Shapiro; Col). Inappropriate prescribing is a leading cause of adverse drug reactions. Fifty percent of adverse drug reactions detected on admission to hospital in one study were from absolutely contraindicated or unnecessary medications (Lindley et al.). Furthermore, there were 0.34 adverse drug reactions for each unnecessary medication and only 0.08 per necessary medications. In a study of nursing home patients, 61 percent of adverse drug reactions were felt to have resulted from inappropriate prescribing (Cooper).

Adverse drug reactions have an important impact on health care use. Of seniors who report experiencing adverse drug reactions, 63 to 75 percent need to contact their physician, 50 percent have laboratory tests ordered, 10 percent visit the emergency room, and 7 to 11 percent are hospitalized (Chrischilles et al., "Selfreported Adverse Drug Reactions"; Hanlon, 1997). When projected to the entire communitydwelling older population, this translates into two million annual physician visits, one million laboratory tests, and 146,000 hospitalizations from adverse drug reactions (Chrischilles et al., "Self-reported Adverse Drug Reactions").

Increases in health care utilization can also be measured in the length of hospital stay or in dollar costs. For patients admitted to hospital who suffered an adverse drug reaction, this occurrence was associated with an increased length of stay of two days and a cost increase of $2,263 (Classen). Results from another study highlights this point: for every dollar spent on medications in nursing facilities, $1.33 is spent in the treatment of medication-induced problems that can be prevented (Bootman et al.).