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a secondary diagnosis of AIDS. Then, consulting with physicians specializing in AIDS 

 care and research, we selected those primary diagnoses that are AIDS-related. These 

 AIDS-related hospital days were added to the hospital days for patients discharged with 

 a primary AIDS diagnosis and then multiplied by the percentage of Intravenous Drug Use 

 (TVDU) as determined by the Center for Disease Control (CDC) AIDS Surveillance (see 

 Footnote 1) to determine substance abuse related AIDS days.' 



Birth complications also required special analysis. Since the abuse of a substance is not 

 responsible for the admission (i.e., the birth itself), but only for certain associated 

 complications, we needed to calculate the marginal impact of those complications. For 

 alcohol, the number of incremental days was a simple calculation of the difference in the 

 number of days where alcohol was indicated as a secondary diagnosis. With respect to 

 the impact of smoking, a PAR was applied to low birth weight babies and the number 

 of days was calculated as described above. However, the length of stay for a normal 

 neonate (2.3 days for each discharge) was deduaed from this since, absent the 

 complication, this number of days still would have been used. For cocaine-exposed 

 babies, costs related to birth complications were estimated based upon a 1986 study by 

 Phibbs, et al of the added days associated with babies exposed to cocaine and other 

 drugs. The results of this study (based upon a multivariate analysis) estimated that, in 



*A similar problem exists for other diseases such as lung cancer where, after the initial diagnosis, 

 fiiture hospitalizations would be for other problems or procedures such as respiratory distress or 

 chemotherapy. However, disentangling the overlap between alternative causes for these other diagnoses 

 and those attributable to the lung cancer made it difficult to count those days in our estimates. Thus, 

 there is reason to believe that our estimates are low since this problem would exist for a number of 

 diagnoses. 



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