> 6.0 mmol/day) was uncommon in patients less than 70 years old with normal renal function (Reardon and Macpherson, 1998); however, data on dietary potassium intake was not collected in this study. Since the 95th percentile estimates of potassium intake for men and women in the United States range from 4.3 to 5.1 g and 2.9 to 3.7 g/day, respectively (Appendix Table D-5), it can be assumed that many of these outpatients had intakes below the AI of 4.7 g (120 mmol)/day.
In case reports additional factors appear to precipitate hyperkalemia in ACE inhibitor-treated patients. These factors include use of potassium supplements, potassium-sparing diuretics, nonsteroidal anti-inflammatory agents, cyclo-oxygenase-2 (COX-2) inhibitors, and heparin (see Box 5-1). Although most case reports relating hyperkalemia and ACE inhibitor treatment occurred in individuals with diabetes, chronic kidney disease, and/or heart failure, there have been a few case reports in other settings. Two cases of hyperkalemia in older men were reported to be due to the use of a potassium-containing salt substitute while taking ACE inhibitor therapy (Ray et al., 1999). One case report documented fatal hyperkalemia in a 77-year-old woman after addition of COX-2 inhibitor therapy to a medical regimen that included an ACE inhibitor and a diet that included a banana each day (Hay et al., 2002). Her serum creatinine had been 0.9 mg/dL, which in retrospect might reflect subtle evidence of chronic kidney disease (Hay et al., 2002). This case illustrates the difficulty of using serum creatinine levels to diagnose early chronic kidney disease. Among older individuals, women who are non-African American often have serum creatinine values that appear to be “normal” (0.9 to 1.2 mg/dL) despite an underlying reduction in kidney function (Culleton et al., 1999).
Overall, because of the concern for hyperkalemia and resultant arrhythmias that might be life-threatening, the proposed AI should not be applied to individuals with chronic kidney disease, heart failure, or type 1 diabetes, especially those who concomitantly use ACE inhibitor therapy. Among otherwise healthy individuals with hypertension on ACE inhibitor therapy, the AI should apply as long as renal function is unimpaired.
Good sources of potassium, as well as bicarbonate precursors, are fruits and vegetables (see Table 5-10). Foods that contain relatively