Epidemiologic trends in the hospitalization of elderly Medicare patients for pneumonia, 1991-1998.

OBJECTIVES: This study determined hospitalization rates of elderly Americans for pneumonia from 1991 through 1998. METHODS: Epidemiologic data were described for 273,143 pneumonia hospitalizations. RESULTS: Annual hospitalizations for aspiration pneumonia increased by 93.5%. Pneumonia hospitalization rates increased steeply with age, especially among men. Black men were at highest risk for aspiration, unspecified, Klebsiella, "other gram-negative," and staphylococcal pneumonia; White men had the highest Haemophilus and pneumococcal pneumonia rates. Among women, Blacks predominated in aspiration and Klebsiella pneumonia; Whites had the highest Haemophilus and bronchopneumonia rates. CONCLUSIONS: An epidemic of hospitalization for aspiration pneumonia smoldered over 8 years. Significant disparities existed in hospitalization risks by race, sex, and principal diagnosis.

Trends and outcomes in the hospitalization of older Americans for cardiac conduction disorders or arrhythmias, 1991-1998.

OBJECTIVE: To identify epidemiological trends and measure outcomes in elderly patients hospitalized for cardiac conduction disorders or arrhythmias. DESIGN: Review of the standard 5% samples of the Medicare Provider Analysis and Review Files to characterize 144,512 discharges from 1991 through 1998 in which the principal diagnosis was a conduction disorder or arrhythmia, using the corresponding Enrollment Databases for denominator data. SETTING: Short-stay hospitals in the United States. PARTICIPANTS: Medicare beneficiaries age 65 and older in the standard 5% sample. MEASUREMENTS: Diagnosis-specific trends and rates; discharges by year; cumulative age-, race-, and sex-specific discharge rates; mean length of stay in hospital and in intensive care; mean Medicare reimbursement to the hospital; case-fatality rate in hospital; discharge destinations of patients discharged alive. RESULTS: Annual hospitalizations for sinoatrial node dysfunction, atrial flutter, atrial fibrillation, or ventricular fibrillation increased more rapidly than did the elderly Medicare beneficiary population. Hospitalizations with a principal diagnosis of ventricular extrasystoles or asystole showed steep secular declines. Discharge rates for sinoatrial node dysfunction, a group of rhythms with a nonsinus pacemaker, atrial fibrillation, Mobitz I, or complete atrioventricular block all increased steeply and continuously with patient age. In contrast, discharge rates for atrial flutter or ventricular tachycardia or fibrillation peaked among 75- to 84-year-old patients. White men were at uniquely high risk of hospitalization for atrial flutter or ventricular tachycardia or fibrillation, and, among the white majority, men had higher discharge rates than women for nine of the 11 commonest rubrics. Whites, particularly white women, had the highest discharge rates for atrial fibrillation. Blacks, especially black women, were at disproportionate risk for hospitalization for the group of nonsinus pacemaker rhythms. Diagnosis-specific mean resource costs were strongly correlated with each other and with mean Medicare reimbursement but not with case-fatality rate. CONCLUSION: Medicare claims data demonstrated striking differences among and within diagnoses of heart blocks or arrhythmias in terms of the populations at greatest risk for hospitalization. This variation should be explored further to generate and test hypotheses about differential causation or delivery of care.

The epidemiology of hospitalization of elderly Americans for septicemia or bacteremia in 1991-1998. Application of Medicare claims data.

PURPOSE: To describe the epidemiology of hospitalization of elderly Americans for septicemia or bacteremia. METHODS: Medicare claims data for discharges from 1991 through 1998 were used to study 75,920 hospitalizations with the principal diagnosis of septicemia or bacteremia in patients aged 65 years or older. RESULTS: "Unspecified septicemia" was the commonest principal diagnosis, followed by septicemia due to Escherichia coli or staphylococci. From 1991 through 1997, annual discharges for "unspecified septicemia" increased 108%, and those for pneumococcal septicemia increased 310%. Decreases in reported septicemia were seen after increases in the proportion of beneficiaries in Medicare health maintenance organizations. Discharge rates for septicemia principal diagnoses increased steeply with age. Age-specific discharge rates were usually highest for black men and lowest for white women. Exceptions included septicemia due to E. coli, with white men at low risk, and pneumococcal septicemia, without significant differences between races or sexes. The case-fatality rate in hospital ranged from 4.2% with "bacteremia" and 6.9% with E. coli septicemia to 22.2% with "septicemia due to gram-negative organism, unspecified," and 26.8% with "unspecified septicemia." Staphylococcal septicemia, septicemia due to pseudomonas, and septicemia due to anaerobes were the costliest common principal diagnoses in terms of the mean duration of hospital stay. CONCLUSIONS: Unexplained sharp increases were reported in hospitalization for septicemia or bacteremia in elderly Americans. Marked variation by race and sex were evident in discharge rates with these principal diagnoses. Prognosis and average cost of treatment also differed substantially among common rubrics. Further investigation of individual diagnoses should concentrate on explaining secular trends, exploring the basis for variation by race and sex, and elucidating risk factors for poor clinical outcomes.

A decision model and cost-effectiveness analysis of colorectal cancer screening and surveillance guidelines for average-risk adults.

OBJECTIVES: Guidelines for colorectal cancer screening and surveillance in people at average risk and at increased risk have recently been published by the American Gastroenterological Association. The guidelines for the population at average risk were evaluated using cost-effectiveness analyses. METHODS: Since colorectal cancers primarily arise from precancerous adenomas, a state transition model of disease progression from adenomatous polyps was developed. Rather than assuming that polyps turn to cancer after a fixed interval (dwell time), such transitions were modeled to occur as an exponential function of the age of the polyps. Screening strategies included periodic fecal occult blood test, flexible sigmoidoscopy, double-contrast barium enema, and colonoscopy. Screening costs in 1994 dollars were estimated using Medicare and private claims data, and clinical parameters were based upon published studies. RESULTS: Cost per life-year saved was $12,636 for flexible sigmoidoscopy every 5 years and $14,394 for annual fecal occult blood testing. The assumption made for polyp dwell time critically affected the attractiveness of alternative screening strategies. CONCLUSIONS: Sigmoidoscopy every 5 years and annual fecal blood testing were the two most cost-effective strategies, but with low compliance, occult blood testing was less cost-effective. Lowering colonoscopy costs greatly improved the cost-effectiveness of colonoscopy every 10 years.

Epidemiologic trends in the evaluation and treatment of lower urinary tract symptoms in elderly male Medicare patients from 1991 to 1995.

PURPOSE: We describe utilization of procedures to reveal recent epidemiologic trends in evaluation and management of benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: Medicare claims data reflect clinical practice in the vast majority of elderly Americans. The standard 5% beneficiary sample from Medicare claims files for 1991 to 1995 was searched to identify men 65 years old or older with invoices containing diagnostic and procedure codes indicative of prostate disease or lower urinary tract symptoms. Physician/supplier file claims for this sample of patients were used to identify diagnostic and therapeutic procedures relevant to BPH. RESULTS: During these 5 years claims for uroflowmetry peaked in 1993, filling cystometry gradually declined and pressure flow studies increased. Transurethral resection of the prostate decreased 43%, with even steeper reductions for open prostatectomy. The proportion of transurethral resections performed in hospital inpatients ebbed from 96 to 88%. Age specific operative rates for transurethral resection were highest in the ninth decade, and during the 5 years operative rates generally declined more among white than black men of the same age. Although urethrocystoscopy and excretory urography explicitly for BPH decreased markedly, from 1992 to 1995 the proportion of transurethral resections preceded by urethrocystoscopy for any indication increased from 45 to 47%, while excretory urograms were still obtained before 36% of these operations in 1992 and decreased to 26% in 1995. CONCLUSIONS: Evaluation and treatment of lower urinary tract symptoms in elderly men in the United States changed rapidly between 1991 and 1995, with a sharp decline in invasive therapy for BPH.

A phospholipase C from the Dallas 1E strain of Legionella pneumophila serogroup 5: purification and characterization of conditions for optimal activity with an artificial substrate.

Phospholipase C from the Dallas 1E strain of Legionella pneumophila serogroup 5 was purified from buffered yeast extract culture supernate by ion-exchange chromatography followed by fractionation by manganous chloride and ammonium sulphate precipitation steps. Enzyme activity was assayed by hydrolysis of p-nitrophenylphosphorylcholine and confirmed by release of radioactivity from tritiated L-alpha-dipalmitoylphosphatidylcholine labelled in the methyl groups of choline. After SDS-PAGE, the purified preparation yielded a single band upon Coomassie-blue staining. This protein migrated with an apparent Mr of 50,000-54,000. Phospholipase C activity was maximal at pH greater than or equal to 8.4 and was enhanced in the presence of sorbitol and of several nonionic detergents but was eliminated by SDS. EDTA, Cu2+, Fe2+ and Zn2+ inhibited enzyme activity, whereas Ba2+, Ca2+, Co2+, Mg2+ and Mn2+ restored activity to EDTA-treated material. No haemolytic activity was demonstrated with the purified enzyme.

Cytolytic and phospholipase C activity in Legionella species.

To examine one possible mechanism of damage to leucocytes and tissue cells in legionellosis, seven species of Legionella were examined for cytolytic activity and for elaboration of phospholipase C, an enzyme that can damage mammalian cell membranes. Cytolysis was assessed using erythrocytes in agar. Phospholipase C was assayed by release of p-nitrophenol from p-nitrophenylphosphorylcholine and of tritiated phosphorylcholine from L-alpha-dipalmitoyl-[choline-methyl-3H]phosphatidylcholine. L. pneumophila, L. bozemanii, L. micdadei, L. dumoffii, L. gormanii, L. longbeachae and L. jordanis all lysed dog red blood cells, which have a high ratio of membrane phosphatidylcholine to sphingomyelin. The same strains hydrolysed varying amounts of p-nitrophenylphosphorylcholine; L. bozemanii exhibited the greatest activity. L. pneumophila, L. bozemanii, L. dumoffii, L. longbeachae and L. jordanis, but not L. micdadei, released tritiated phosphorylcholine from labelled substrate. These results indicate that several species of Legionella possess cytolytic capability; exotoxins with activity may play a role.

Febrile illness in successive cohorts of tourists at a hotel on the Italian Adriatic coast: evidence for a persistent focus of Legionella infection.

Outbreaks of febrile illness consistent with legionellosis occurred in successive groups of vacationers at an Adriatic resort in 1980. Illness was associated with one of two hotels used by the groups. A cohort study of guests of the suspect hotel revealed 23 cases of febrile illness with pulmonary symptoms, significant antibody titers to Legionella pneumophila, or both, among 291 persons at risk. Two patients died. Attack rates ranged from 0-19% in the nine cohorts of vacationers and were highest among the most elderly. Febrile illness in the last two cohorts of the season was associated with an antibody titer greater than or equal to 128. L. pneumophila was isolated from shower heads in the suspect hotel, but no association was found between showering and illness or seropositivity. Bacteria identified as L. pneumophila by direct immunofluorescence were also found in water from an adjacent hotel and from the outflow from a common well. No cases were associated with the adjacent hotel.

Mammaplasty-associated mycobacterial infection: a survey of plastic surgeons.

In a 3 1/2-year period, periprosthetic infections due to Mycobacterium fortuitum complex organisms complicated augmentation mammaplasty in at least 17 women. To determine the magnitude of the problem and to identify possible risk factors for infection, we conducted a questionnaire survey of 2062 members of the American Society of Plastic and Reconstructive Surgeons who had performed approximately 64,00 augmentation mammaplasties in 1978. Information about selected aspects of the procedures and practices in use with augmentation mammaplasty and about patients for whom augmentation mammaplasty had been performed was supplied by 67 percent of those surveyed. The estimated attack rate of wound infection after augmentation mammaplasty caused by all organisms was 0.64 percent. Only 5 cases of mycobacterial wound infection were documented after 39,455 augmentation procedures in 1978. Periprosthetic infection due to Mycobacterium fortuitum complex organisms appears, for the most part, to be a sporadic event that may occur after simple augmentation mammaplasty, subcutaneous mastectomy with augmentation, or reduction mammaplasty.

Infection due to organisms of the Mycobacterium fortuitum complex after augmentation mammaplasty: clinical and epidemiologic features.

Periprosthetic infections due to Mycobacterium fortuitum and Mycobacterium chelonei occurred in 17 women over a 3.5-year period after implantation of prostheses for breast augmentation. The median incubation period for 16 of the women was 28 days (range, one week to over two years) after surgery; etiologic diagnosis was usually delayed for weeks to months. Odorless and serosanguineous or purulent material was found when the implants were removed, and acid-fast bacilli were often present when smears were examined. Wound infections were chronic and refractory to therapy with various antimicrobial agents. Persistent or recurrent mycobacterial infections complicated attempts to implant new prostheses. Whereas M. fortuitum isolates were susceptible to amikacin, multiple strains of M. fortuitum were distinguished by conventional antituberculous and broth microdilution susceptibility tests. Several clusters of infections were temporally and geographically related; however, sporadic cases were also reported, and no evidence of a contaminated common product or other single source of infection was found.

Isolation and characterization of hypertoxinogenic (htx) mutants of Escherichia coli KL320(pCG86).

The structural genes for heat-labile enterotoxin (LT) are present on plasmid pCG86. Escherichia coli KL320(pCG86), LT was found to be cell associated. LT was present as a soluble protein in sonic lysates of KL320(pCG86). Thirty-one mutants of KL320(pCG86) that produced increased amounts of extracellular LT were isolated. These hypertoxinogenic (htx) mutants were assigned to four phenotypically distinct classes based on the amounts of cell-associated and extracellular LT in early-stationary-phase cultures. Type 1 and type 2 htx mutants produced significantly increased amounts of cell-associated LT. Type 3 and type 4 htx mutants produced normal or decreased amounts of cell-associated LT was similar to that of the wild type. In the mutants of types 1, 3, and 4, the ratios of extracellular to cell-associated LT were higher than that of the wild type and were characteristic for each strain. Cell lysis or leakage of macromolecular cytoplasmic constituents appeared to be significant for release of LT by mutants of types 1, 3, and 4, because supernatants from cultures of these mutants also contained increased amounts of protein and of the cytoplasmic enzyme glucose 6-phosphate dehydrogenase. In all four representative htx mutants, the hypertoxinogenic phenotypes were dependent on chromosomal mutations. The resident pCG86 plasmids were eliminated from the htx mutants of types 2 and 3. After wild-type plasmid pCG86 was introduced into the cured strains by conjugation, their hypertoxinogenic phenotypes were restored. We conclude that chromosomal loci in E. coli KL320 are important in regulating expression of the LT structural genes of plasmid pCG86.

The chest roentgenogram in sporadic cases of Legionnaires' disease.

We reviewed chest roentgenograms from 17 persons with confirmed Legionnaires' disease. None of the cases was associated with known outbreaks. Pulmonary infiltrates, usually extensive, were present in all cases. The predominant radiological pattern of both on initial roentgenograms and those from the peak of illness was distal air space disease, usually in a segmental or lobar distribution. The lower lobes were involved most frequently. Pleural effusion and volume loss were infrequent. Radiological findings progressed rapidly and often cleared rapidly, although slow clearing was also seen in some cases. Legionnaires' disease should be included in the radiological differential diagnosis of segmental or lobar pneumonia.

Epidemic neonatal gentamicin-methicillin--resistant Staphylococcus aureus infection associated with nonspecific topical use of gentamicin.

One hundred sixteen infants in an intensive care nursery acquired Staphylococcus aureus resistant to gentamicin and methicillin; 54 patients acquired S. aureus sensitive to gentamicin and methicillin. Topical application of gentamicin ointment was significantly associated with acquisition of GMRS. Of 78 infants who acquired GMRS, 38 had received GmO before GMRS was first cultured, whereas only one of 49 infants with GMSS had previously received GmO (P = 8.6 X 10(-8)). Infants with GMRS were also more likely than patients with GMSS to have had a lower mean birth weight, Apgar score, and gestational age; systemic antibiotic therapy and incubator care were significantly prolonged for patients with GMRS, but these factors did not explain susceptibility to GMRS infection. Multivariate logistic regression analysis showed that use of GmO was the single most important risk factor.

Recurrence of Pelecypod-associated cholera in Sardinia.

From Oct. 30 to Nov. 7, 1979, 10 people in the Sardinian province of Cagliari had onset of bacteriologically confirmed cholera. Two symptom-free excretors of Vibrio cholerae O:1 were detected in household contacts of the patients. There were no deaths. All but 1 of the 12 people with V. cholerae O:1 infection gave a history of recent consumption of marine bivalves known locally as arselle (pelecypods). Triplicate matched neighbourhood controls for each of the first 7 cases identified were also interviewed; none had recently eaten arselle. V. cholerae O:1 was also recovered from samples of water and bivalves obtained from a lagoon on the outskirts of the city of Cagliari. Arselle had also been implicated as the vehicle of transmission in 1973 in the last outbreak of cholera in Sardinia. It seems unlikely that cholera transmission had persisted locally in the interim.

Prolonged intermittent diarrhea after Shiga dysentery: postdysenteric syndrome.

A 42-year-old woman had dysentery caused by the Shiga bacillus, Shigella dysenteriae type 1, while taking diphenoxylate with atropine during and after her return from a trip to Mexico. Although she was treated with appropriate antibiotics, she suffered a prolonged and toxic acute course followed by intermittent bouts of diarrhea and abdominal cramping which persisted for two years. The risk of confusing Shiga dysentery with ulcerative colitis is illustrated by the presentation, management, and prolonged course of this patient's illness.

Legionnaires' disease bacterium: prevalence of antibody reacting with the organism in patients suspected of having infection with Pneumocystis carinii.

Using indirect immunofluorescence, we examined 713 serum specimens submitted for Pneumocystis carinii serologic studies from 566 patients for antibody to the Legionnaires' disease bacterium. This group was chosen because it presumably consisted largely of immunosuppressed patients with acute respiratory illnesses. Of patients tested, 3.4% had titers of 1:128 or greater to Legionella pneumophila. Four (3.7%) of 107 patients for whom multiple specimens were submitted showed diagnostic increases in titer. The proportion of seropositive specimens did not vary with the age, sex, or geographic location of the patients or with season of the year in which the specimens were submitted. In a separate group of 138 serum specimens from 48 patients undergoing marrow transplantation, only 1 seropositive specimen was detected. No estimate of incidence is possible from these studies, but serologic evidence of past or current infection with Legionella pneumophila is uncommon in patients in whom Pneumocystis carinii pneumonia is suspected on clinical grounds. Nevertheless, Legionnaires' disease can affect the immunosuppressed host and should be considered in the differential diagnosis of pneumonia in such a patient.