Congestive Heart Failure in the United States: Is There More Than Meets the I(CD Code)? The Corpus Christi Heart Project

Background. Congestive heart failure (CHF) is increasing as a public health problem in the United States. The ability to quantify this problem has been limited by a lack of data regarding the validity of CHF identification. Objective. To assess the validity of the use of International Classification of Disease, Ninth Revision, Clinical Modification (ICD) codes to identify hospitalizations with clinical evidence of an episode of acute CHF in data of The Corpus Christi Heart Project, a population-based surveillance program for hospitalized coronary heart disease. Methods. The validation standard was a composite variable including the presence of physician diagnosed acute CHF or radiographic evidence of pulmonary edema. Data were abstracted from the medical records of 5083 patients identified as hospitalized for possible acute myocardial infarction, aortocoronary bypass surgery, percutaneous transluminal coronary angioplasty, and related revascularization procedures in the Corpus Christi Heart Project. Discharge diagnoses, a secondary source of data, were used to apply 3 computer algorithms to assess the assignment of ICD codes. Results. The prevalence of clinically documented CHF was 27.1% (1376/5083). The ICD code 428 (CHF), assigned as the primary or a secondary discharge diagnosis, was associated with 62.8% sensitivity, as 95.4% specificity, 83.5% positive predicitive value, 87.4% negative predictive value, and a 24.8% undernumeration of CHF-related hospitalizations. An algorithm based on a series of ICD codes was associated with 67.1% sensitivity, 92.6% specificity, 77.1% positive predictive value, 88.3% negative predictive value, and a 13.0% undernumeration of CHF-related hospitalizations. Conclusions. Reliance on ICD codes results in the exclusion of one third of the patients with clinical evidence of acute CHF. This undernumeration is compounded by the typical reliance on the first listed diagnosis. Congestive heart failure may be a greater public health problem than currently recognized. The allocation of resources for relevant surveillance, research, medical care, and preventive efforts should be reevaluated.—Goff DC, Pandey DK, Chan FA, et al. Congestive heart failure in the United States: Is there more than meets the I(CD code)? The Corpus Christi Heart Project. Arch Intern Med. 2000;160:197–202. Comment. This year our nation is undergoing a national census. A major impetus for obtaining accurate assessments of the demographics around the country is so that each designated region receives their fair representation in Congress, and that this region also receives its appropriate share of resources. Having said this, the authors of this manuscript, address analagous issues in health care. As our population of senior citizens increases, so does the problem of treating patients with the syndrome of congestive heart failure. As our ability to treat patients with ischemic heart disease has improved and more patients survive acute myocardial infarction, we have markedly increased the number of patients who suffer from significant left ventricular dysfunction. While we as clinicians intuitively recognize this, the magnitude of the problem needs to be quantified so that our increasingly limited health care resources can be appropriately allocated. Based on the data in this study, the authors were able to conclude that the standard International Class of Diseases codes that we use today leads to a significant under-recognition of the numbers of patients who suffer from congestive heart failure. Therefore, we must recognize that it may be a much bigger problem than current figures show. We should, consider developing more sensitive criteria for assessing the magnitude of the problem. By doing so, our health care system can then devote its resources more prudently. This approach has proved to be cost effective. This will undoubtedly translate into better care and more preventive efforts for patients who are at risk for this problem, and ultimately improve our cardiovascular health care delivery system.