Use of surgery in patients with native valve infective endocarditis: results from the International Collaboration on Endocarditis Merged Database

BACKGROUND

Early surgery has been shown to be beneficial for patients with infective endocarditis (IE), yet surgery is not used in most patients. Evidence of the uncertainty around the use of surgery can be found in the wide variations in the use of cardiac surgery in IE with few precise indications for cardiac surgery yet defined. The aim of the study was to characterize patients with native valve IE relative to surgery and to determine if patients who benefit from an early surgical intervention can be identified.

METHODS

The International Collaboration on Endocarditis Merged Database was used to quantify the differences between patients with IE receiving medical and surgical intervention in 1516 patients with definite native valve IE. Propensity models were built to identify a group of patients that benefit from early surgery.

RESULTS

Patients in the early surgical group were more likely to be male, younger, and with less comorbidities compared with the early medical group (P < .001 for all) and were less likely to have infection with Staphylococcus aureus or viridans group streptococci (P < .05 for all). Intracardiac abscess and heart failure were much more common in the surgical group (P < .001 for all). In an unadjusted comparison, there was no statistically significant survival advantage in the surgical group. However, in the propensity analysis, in the subgroup of patients with the most indications for surgery, there was a significant decrease in mortality associated with early surgery (11.2% vs 38.0%, P < .001).

CONCLUSIONS

The benefits of surgery are not seen uniformly in all patients with native valve IE, but are most realized in a targeted population. This observation requires confirmation in other populations of patients with definite IE.

The use and effect of surgical therapy for prosthetic valve infective endocarditis: a propensity analysis of a multicenter, international cohort

BACKGROUND

Although surgical intervention is often used in the treatment of prosthetic valve infective endocarditis (PVIE), an understanding of its effect on survival has been limited by the biases of observational studies and lack of controlled trials.

METHODS

The International Collaboration on Endocarditis Merged Database is a large, multicenter, international registry of patients with definite endocarditis by Duke criteria, including 367 patients with PVIE. Clinical, microbiologic, and echocardiographic variables were analyzed to determine those factors associated with the use of surgery for PVIE. Logistic regression analysis was performed to create a propensity model of predictors of surgery use. Patients who underwent surgery during initial hospitalization were matched by propensity score with patients treated with medical therapy alone. Logistic regression analysis was performed to determine variables independently associated with inhospital mortality in this matched subset.

RESULTS

Surgical therapy for PVIE was performed in 148 (42%) of 367 patients. Inhospital mortality was similar for patients treated with surgery compared with those treated with medical therapy alone (25.0% vs 23.4%, P = .729). Surgical therapy was independently associated with patient age, microorganism, intracardiac abscess, and congestive heart failure. After adjustment for these determinants, inhospital mortality was predicted by brain embolization (OR 11.12, 95% CI 4.16-29.73) and Staphylococcus aureus infection (OR 3.67, 95% CI 1.29-9.74), with a trend toward benefit for surgery (OR 0.56, 95% CI 0.23-1.36).

CONCLUSIONS

Despite the frequent use of surgery for the treatment of PVIE, this condition continues to be associated with a high inhospital mortality rate in the contemporary era. After adjustment for factors related to surgical intervention, brain embolism and S aureus infection were independently associated with inhospital mortality and a trend toward a survival benefit of surgery was evident.

Clinical characteristics and outcome of aortic endocarditis with periannular abscess in the International Collaboration on Endocarditis Merged Database

The aims of this study were to determine the clinical characteristics and outcome of patients who had definite infective endocarditis (IE) complicated by aortic ring abscess formation that was detected with transesophageal echocardiography (TEE) and to determine the prognostic significance of abscess formation in aortic valve IE. Patients who had aortic valve IE were selected from the International Collaboration on Endocarditis Merged Database (ICE-MD) if they underwent TEE. Among 311 patients who had definite aortic valve IE, 67 (22%) had periannular abscesses. They were more likely to have infection in the setting of a prosthetic valve (40% vs 19%, p <0.001) and coagulase-negative staphylococcal IE (18% vs 6%, p < 0.01) and less likely to have streptococcal IE than were patients who did not develop abscess (28% vs 46%, p = 0.01). Systemic embolization, central nervous system events, and heart failure did not differ between those who developed abscess and those who did not, but power was limited. Patients who had abscess were more likely to undergo surgery (84% vs 36%, p <0.001), and their in-hospital mortality rate was higher (19% vs 11%, p = 0.09). Multivariate analysis of prognostic factors of mortality in aortic IE identified age (odds ratio [OR] 1.6, 95% confidence interval [CI]1.2 to 2.1), Staphylococcus aureus (S. aureus) infection (OR 2.4, 95% CI 1.1 to 5.2), and heart failure (OR 2.9, 95% CI 1.4 to 6.1) as variables that were independently associated with increased risk of death. Periannular abscess formation showed a nonsignificant trend toward an increased risk of death (OR 1.9, 95% CI 0.9 to 3.8). Multivariate analysis of prognostic factors of mortality in complicated aortic IE with abscess formation identified S. aureus infection (OR 6.9, 95% CI 1.6 to 29.4) as independently associated with increased risk of death. In conclusion, in the current era of TEE and high use of surgical treatment, periannular abscess formation in aortic valve IE is not an independent risk factor for mortality. S. aureus infection is an independent prognostic factor for mortality in patients who have abscess formation.

Enterococcal endocarditis: 107 cases from the international collaboration on endocarditis merged database

PURPOSE

To describe clinical features and outcomes of enterococcal left-sided native valve endocarditis and to compare it to endocarditis caused by other pathogens.

SUBJECTS AND METHODS

Patients in the International Collaboration on Endocarditis-Merged Database were included if they had left-sided native valve endocarditis. Demographic characteristics, clinical features, and outcomes were analyzed. Multivariable analysis evaluated enterococcus as a predictor of mortality.

RESULTS

Of 1285 patients with left-sided native valve endocarditis, 107 had enterococcal endocarditis. Enterococcal endocarditis was most frequently seen in elderly men, frequently involved the aortic valve, tended to produce heart failure rather than embolic events, and had relatively low short-term mortality. Compared to patients with non-enterococcal endocarditis, patients with enterococcal endocarditis had similar rates of nosocomial acquisition, heart failure, embolization, surgery, and mortality. Compared to patients with streptococcal endocarditis, patients with enterococcal endocarditis were more likely to be nosocomially acquired (9 of 59 [15%] vs 2 of 400 [1%]; P <.0001) and have heart failure (49 of 107 [46%] vs 234 of 666 [35%]; P = 0.03). Compared to patients with S. aureus endocarditis, patients with enterococcal endocarditis were less likely to embolize (28 of 107 [26%] vs 155 of 314 [49%]; P <.0001) and less likely to die (12 of 107 [11%] vs 83 of 313 [27%]; P = 0.001). Multivariable analysis of all patients with left-sided native valve endocarditis showed that enterococcal endocarditis was associated with lower mortality (odds ratio [OR] 0.49; 95% confidence interval [CI] 0.24 to 0.97).

CONCLUSIONS

Enterococcal native valve endocarditis has a distinctive clinical picture with a good prognosis.

Staphylococcus aureus endocarditis: a consequence of medical progress

CONTEXT

The global significance of infective endocarditis (IE) caused by Staphylococcus aureus is unknown.

OBJECTIVES

To document the international emergence of health care-associated S aureus IE and methicillin-resistant S aureus (MRSA) IE and to evaluate regional variation in patients with S aureus IE.

DESIGN, SETTING, AND PARTICIPANTS

Prospective observational cohort study set in 39 medical centers in 16 countries. Participants were a population of 1779 patients with definite IE as defined by Duke criteria who were enrolled in the International Collaboration on Endocarditis-Prospective Cohort Study from June 2000 to December 2003.

MAIN OUTCOME MEASURE

In-hospital mortality.

RESULTS

S aureus was the most common pathogen among the 1779 cases of definite IE in the International Collaboration on Endocarditis Prospective-Cohort Study (558 patients, 31.4%). Health care-associated infection was the most common form of S aureus IE (218 patients, 39.1%), accounting for 25.9% (Australia/New Zealand) to 54.2% (Brazil) of cases. Most patients with health care-associated S aureus IE (131 patients, 60.1%) acquired the infection outside of the hospital. MRSA IE was more common in the United States (37.2%) and Brazil (37.5%) than in Europe/Middle East (23.7%) and Australia/New Zealand (15.5%, P<.001). Persistent bacteremia was independently associated with MRSA IE (odds ratio, 6.2; 95% confidence interval, 2.9-13.2). Patients in the United States were most likely to be hemodialysis dependent, to have diabetes, to have a presumed intravascular device source, to receive vancomycin, to be infected with MRSA, and to have persistent bacteremia (P<.001 for all comparisons).

CONCLUSIONS

S aureus is the leading cause of IE in many regions of the world. Characteristics of patients with S aureus IE vary significantly by region. Further studies are required to determine the causes of regional variation.

Emergence of endocarditis due to group D streptococci: findings derived from the merged database of the International Collaboration on Endocarditis

The aim of the present study was to compare the epidemiological and clinical characteristics of Streptococcus bovis endocarditis with those of endocarditis caused by oral streptococci, using data obtained from a large international database of uniformly defined cases of infective endocarditis. S. bovis, a well-known cause of infective endocarditis, remains the common name used to designate group D nonenterococcal streptococci. In some countries, the frequency of S. bovis endocarditis has increased significantly in recent years. Data from the International Collaboration on Endocarditis merged database was used to identify the main characteristics of S. bovis endocarditis and compared them with those of infective endocarditis (IE) due to oral streptococci. The database contained 136 cases of S. bovis IE and 511 cases of IE due to oral streptococci. Patients with S. bovis IE were significantly older those with IE due to oral streptococci (63+/-16 vs. 55+/-18 years, P<0.00001). The proportion of streptococcal IE due to S. bovis increased from 10.9% before 1989 to 23.3% after 1989 (P=0.0007) and was 56.7% in France as compared with 9.4% in the rest of Europe and 6.0% in the USA (P<0.00001). Patients with S. bovis IE had more comorbidity and never used intravenous drugs. Complication rates, rates of valve replacement, and mortality rates were similar in the two groups. In conclusion, this study confirmed that S. bovis IE has unique characteristics when compared to endocarditis due to oral streptococci and that it emerged in the 1990s, mainly in France, a finding that is yet unexplained.

Aorto-cavitary fistulous tract formation in infective endocarditis: clinical and echocardiographic features of 76 cases and risk factors for mortality

AIMS

To investigate the clinical features, echocardiographic characteristics, management, and prognostic factors of mortality of aorto-cavitary fistulization (ACF) in infective endocarditis (IE). Extension of infection in aortic valve IE beyond valvular structures may result in peri-annular complications with resulting necrosis and rupture, and subsequent development of ACF. Aorto-cavitary communications create intra-cardiac shunts, which may result in further clinical deterioration and haemodynamic instability.

METHODS AND RESULTS

In a retrospective multi-centre study over 4681 episodes of IE, a total of 76 patients with ACF [1.6%, confidence interval (CI) 95%: 1.2-2.0%] diagnosed by echocardiography or during surgery were identified. Fistulae were found in 1.8% of cases of native valve IE and in 3.5% of cases of prosthetic valve IE from the general population and in 0.4% of drug abusers. PVE was present in 31 (41%) cases of ACF. Transthoracic and transoesophageal echocardiography detected the fistulous tracts in 53 and 97% of cases, respectively. Peri-annular abscesses were detected in 78% of cases, fistulae originated in similar rates from the three sinuses of Valsalva, and the four cardiac chambers were equally involved in the fistulous tracts. Heart failure (HF) developed in 62% of cases and surgery was performed in 66 (87% CI 95% 77-93%) patients with a mortality of 41% (95% CI 30-53%) in the overall population. Multivariate analysis identified HF (OR 3.4, CI 95% 1.0-11.5), prosthetic IE (OR 4.6, CI 95% 1.4-15.4) and urgent or emergency surgical treatment (OR 4.3, CI 95% 1.3-16.6) as variables significantly associated with an increased risk of death. Major complications during follow-up (death, re-operation, or re-admission for HF) among the five operative survivors with residual fistulae occurred in 20 and 100% of patients at 1 and 2 years, respectively.

CONCLUSION

Aorto-cavitary fistulous tract formation is an uncommon but extremely serious complication of IE. In-hospital mortality was exceptionally high despite aggressive management with surgical intervention in the majority of patients. Prosthetic IE, urgent surgery, and the development of HF identify the subgroup of patients with IE and ACF that have significantly increased risk of in-hospital death.

Native valve endocarditis due to coagulase-negative staphylococci: report of 99 episodes from the International Collaboration on Endocarditis Merged Database

Using a large cohort of patients from the International Collaboration on Endocarditis Merged Database, we compared coagulase-negative staphylococcal (CoNS) native-valve endocarditis (NVE) to NVE caused by more common pathogens. Rates of heart failure and mortality were similar between patients with CoNS NVE and patients with Staphylococcus aureus NVE, but rates for both groups were significantly higher than rates for patients with NVE due to viridans streptococci. These results emphasize the importance of CoNS as a cause of NVE and the potential for serious complications with this infection.

Candida endocarditis: contemporary cases from the International Collaboration of Infectious Endocarditis Merged Database (ICE-mD)

Candida infective endocarditis (IE) is increasingly common, yet most reports have been single-center reviews. We evaluated 16 patients with Candida IE nested within a cohort of 2,022 patients with IE. Prosthetic valve IE was more common in patients with Candida (50% vs 17%); mortality was 37% for patients with Candida.

Prognostic factors in 61 cases of Staphylococcus aureus prosthetic valve infective endocarditis from the International Collaboration on Endocarditis merged database

Staphylococcus aureus prosthetic valve infective endocarditis (SA-PVIE) is associated with a high mortality rate, but prognostic factors have not been clearly elucidated. The International Collaboration on Endocarditis merged database (ICE-MD) contained 2212 cases of definite infective endocarditis (as defined using the Duke criteria), 61 of which were SA-PVIE. Overall mortality rate was 47.5%, stroke was associated with an increased risk of death, and early valve replacement was not associated with a significant survival benefit in the whole population; however, patients who developed cardiac complications and underwent early valve replacement had the lowest mortality rate (28.6%).

Infective endocarditis not related to intravenous drug abuse in HIV-1-infected patients: report of eight cases and review of the literature

OBJECTIVES

To add to the limited information on infective endocarditis (IE) not related to intravenous drug abuse (IVDA) in HIV-1-infected patients.

METHODS

We have reviewed the characteristics of eight cases of IE in non-IVDA HIV-1 infected patients diagnosed in our institution between 1979 and 1999 as well as cases in the literature.

RESULTS

All our patients were male, and the mean age was 44 years (range 29-64). HIV-1 risk factors were: homosexuality in five, heterosexuality in two, and the use of blood products in one. HIV stage C was found in six cases, and the median (range) CD4 cell count was 22/microL (4-274 cells/microL). IE was caused by Enterococcus faecalis in three cases, staphylococci in two cases, and Salmonella enteritidis, viridans group streptococci and Coxiella burnetii in one case each. Three patients acquired IE while in the hospital. All IE cases involved a native valve, and underlying valve disease was found in three patients. The aortic valve was the most frequently affected (five cases). Two patients underwent surgery, with a good outcome, and one patient died. Fourteen cases of IE not related to IVDA in HIV-1-infected patients were found in the literature review. The most common causative agents were Salmonella spp. and fungi (four cases each). Two patients had prosthetic valve IE, and the mitral valve was the most frequently affected (10 cases). The remaining clinical characteristics and the outcome were similar to those in the present series.

CONCLUSIONS

IE not related to IVDA is rare in HIV-1-infected patients. In more than half of the cases, IE develops in patients with advanced HIV-1 disease. A wide etiologic range is found, reflecting different clinical and environmental conditions. None of the patients who underwent surgery died, and the overall mortality rate was not higher than in non-HIV-1-infected patients with IE.

Streptococcus agalactiae infective endocarditis: analysis of 30 cases and review of the literature, 1962-1998

We describe 30 cases (1.7%) of community-acquired penicillin-susceptible Streptococcus agalactiae endocarditis among 1771 episodes of endocarditis diagnosed in 4 Spanish hospitals from 1975 through 1998. Endocarditis affected a native valve (most often the mitral valve) in 25 cases (83%). Surgical valve replacement was performed for 12 patients (40%). Fourteen patients (47%) died. Mortality rates for patients with native and prosthetic valve endocarditis were 36% and 100%, respectively (P=.01). The mortality rate for native valve endocarditis decreased during the last 6 years of the study (from 61% in 1975-1992 to 8% in 1993-1998; P<.05). Additionally, 115 cases in the literature from 1962-1998 were reviewed. During 1980-1998, the percentage of patients who underwent cardiac surgery increased from 24% (in the previous period, 1962-1979) to 43% (P=.05) and the mortality rate decreased from 45% to 34% (P=NS). S. agalactiae is an uncommon cause of endocarditis with a high mortality rate, although the prognosis of native valve endocarditis has improved in recent years, probably because of an increased use of cardiac surgery.

Immunoblot profile as predictor of toxoplasmic encephalitis in patients infected with human immunodeficiency virus

In order to define more accurately human immunodeficiency virus-infected patients at risk of developing toxoplasmic encephalitis (TE), we assessed the prognostic significance of the anti-Toxoplasma gondii immunoglobulin G (IgG) immunoblot profile, in addition to AIDS stage, a CD4(+) cell count <50/mm(3), and an antibody titer > or =150 IU/ml, in patients with CD4 cell counts <200/mm(3) and seropositive for T. gondii. Baseline serum samples from 152 patients included in the placebo arm of the ANRS 005-ACTG 154 trial (pyrimethamine versus placebo) were used. The IgG immunoblot profile was determined using a Toxoplasma lysate and read using the Kodak Digital Science 1D image analysis software. Mean follow-up was 15.1 months, and the 1-year incidence of TE was 15.9%. The cumulative probability of TE varied according to the type and number of anti-T. gondii IgG bands and reached 65% at 12 months for patients with IgG bands of 25 and 22 kDa. In a Cox model adjusted for age, gender, Centers for Disease Control and Prevention (CDC) clinical stage, and CD4 and CD8 cell counts, the incidence of TE was higher when the IgG 22-kDa band (hazard ratio [HR] = 5.4; P < 0.001), the IgG 25-kDa band (HR = 4.7; P < 0.001), or the IgG 69-kDa band (HR = 3.4; P < 0.001) was present and was higher for patients at CDC stage C (HR = 4.9; P < 0.001). T. gondii antibody titer and CD4 cell count were not predictive of TE. Thus, detection of IgG bands of 25, 22, and/or 69 kDa may be helpful for deciding when primary prophylaxis for TE should be started or discontinued, especially in the era of highly active antiretroviral therapy.

A randomized trial of the discontinuation of primary and secondary prophylaxis against Pneumocystis carinii pneumonia after highly active antiretroviral therapy in patients with HIV infection. Grupo de Estudio del SIDA 04/98

BACKGROUND

Prophylaxis against Pneumocystis carinii pneumonia is indicated in patients with human immunodeficiency virus (HIV) infection who have less than 200 CD4 cells per cubic millimeter and in those with a history of P. carinii pneumonia. However, it is not clear whether prophylaxis can be safely discontinued after CD4 cell counts increase in response to highly active antiretroviral therapy.

METHODS

We conducted a randomized trial of the discontinuation of primary or secondary prophylaxis against P. carinii pneumonia in HIV-infected patients with a sustained response to antiviral therapy, defined by a CD4 cell count of 200 or more per cubic millimeter and plasma HIV type 1 (HIV-1) RNA level of less than 5000 copies per milliliter for at least three months. Prophylactic treatment was restarted if the CD4 cell count declined to less than 200 per cubic millimeter.

RESULTS

The 474 patients receiving primary prophylaxis had a median CD4 cell count at entry of 342 per cubic millimeter, and 38 percent had detectable HIV-1 RNA. After a median follow-up period of 20 months (758 person-years), there had been no episodes of P. carinii pneumonia in the 240 patients who discontinued prophylaxis (95 percent confidence interval, 0 to 0.85 episode per 100 person-years). For the 113 patients receiving secondary prophylaxis, the median CD4 cell count at entry was 355 per cubic millimeter, and 24 percent had detectable HIV-1 RNA. After a median follow-up period of 12 months (123 person-years), there had been no episodes of P. carinii pneumonia in the 60 patients who discontinued prophylaxis (95 percent confidence interval, 0 to 4.5 episodes per 100 person-years).

CONCLUSIONS

In HIV-infected patients receiving highly active antiretroviral therapy, primary and secondary prophylaxis against P. carinii pneumonia can be safely discontinued after the CD4 cell count has increased to 200 or more per cubic millimeter for more than three months.

Residual low-level viral replication could explain discrepancies between viral load and CD4+ cell response in human immunodeficiency virus-infected patients receiving antiretroviral therapy

We report the evolution of chronic infection with human immunodeficiency virus type 1 (HIV-1) in a patient treated with stavudine plus didanosine, whose CD4+ lymphocyte count progressively decreased, despite a sustained plasma viral load <20 copies/mL. After 12 months of therapy, treatment was switched to zidovudine plus lamivudine plus nelfinavir. CD4+ T cell count decreased from 559 x 10(6)/L at month 0 to 259 x 10(6)/L at month 12. Plasma viral load decreased from 21,665 HIV-1 RNA copies/mL at baseline (month 0) to <20 copies/mL after 1 month of therapy with stavudine plus didanosine, and remained below 20 copies/mL until month 12, but always >5 copies/mL. Viral load in tonsilar tissue at month 12 was 125,000 copies/mg of tissue. After the change to triple-drug therapy, the plasma viral load decreased to 5 copies/mL, the CD4+ T cell count increased to 705 x 10(6)/L, and the viral load in tonsilar tissue decreased to <40 copies/mg of tissue at month 24. A low level of HIV-1 replication could explain the lack of immunologic response in patients with apparent virological response.

Six-year experience with cryopreserved mitral homografts in the treatment of tricuspid valve endocarditis in HIV-infected drug addicts

BACKGROUND AND AIM OF THE STUDY

In the past, valve homografts have been used in the treatment of aortic endocarditis. This report details our experience in tricuspid valve replacement using cryopreserved mitral homografts in HIV-positive drug addicts with infective endocarditis.

METHODS

Five HIV-1-infected drug addicts with active uncontrollable tricuspid valve endocarditis underwent tricuspid valve replacement with a cryopreserved mitral homograft.

RESULTS

There was no early mortality, and median follow up was 5 years (range: 1 to 6 years). One late mortality occurred as a result of heroin overdose. Three of the five patients developed six episodes of recurrent bacterial tricuspid endocarditis on the homograft; these were cured successfully with antibiotics. All survivors remain in NYHA functional class I. The latest transthoracic echocardiography examination showed mild, moderate or severe regurgitation in one, two and two patients, respectively. To date, neither homograft calcification nor rupture of the papillary muscle has been detected.

CONCLUSIONS

This novel technique is considered to be an adequate approach to these cases of uncontrollable infectious disease. Further episodes of valvular infection can be managed medically.

Efficacy of azithromycin or clarithromycin for prophylaxis of viridans group streptococcus experimental endocarditis

The efficacy of azithromycin or clarithromycin was compared to that of amoxicillin, clindamycin, or erythromycin for the prevention of viridans group streptococcus experimental endocarditis. Rabbits with catheter-induced aortic valve vegetations were given no antibiotics or two doses of amoxicillin at 25 mg/kg of body weight, azithromycin at 10 mg/kg, clarithromycin at 10 mg/kg, clindamycin at 40 mg/kg followed by clindamycin at 20 mg/kg, or erythromycin at 10 mg/kg. Antibiotics were administered 0.5 h before and 5.5 h after intravenous infusion of 5 x 10(5) CFU of Streptococcus milleri. Forty-eight hours after bacterial inoculation, the rabbits were killed and aortic valve vegetations were aseptically removed and cultured for bacteria. Infective endocarditis occurred in 88% of untreated animals, 1% of animals receiving amoxicillin, 9% of animals receiving erythromycin, 0% of animals receiving clindamycin, 2.5% of animals receiving clarithromycin, and 1% of animals receiving azithromycin. All five regimens were more effective (P < 0.001) than no prophylaxis. Erythromycin was less effective (P < 0.05) than amoxicillin or clindamycin. Azithromycin or clarithromycin was as effective as amoxicillin, clindamycin, or erythromycin for the prevention of viridans group streptococcus experimental endocarditis in this model.

Switching from zidovudine to didanosine in patients with symptomatic HIV infection and disease progression. ddI Iberian Study Group

This study evaluated the efficacy of switching to didanosine in patients who were clinically or immunologically progressing despite zidovudine therapy. This multicenter, open-label study involved 400 patients with the acquired immunodeficiency syndrome (AIDS) or AIDS-related complex (ARC), who had tolerated zidovudine for at least 12 weeks and had signs of clinical or immunological disease progression. They were randomly assigned to receive 600 mg/d of zidovudine (n=133), 500 mg/d of didanosine (n=131), or 200 mg/d of didanosine (n=136). The primary end point was a new AIDS-defining event or death. The study was prematurely terminated, after the first interim analysis, mainly owing to results of two controlled studies demonstrating that a change to didanosine was associated with an improved outcome in patients with advanced HIV-1 disease. The median duration of follow-up was 53 weeks. The primary end point rates were 41, 58, and 59 (per 100 person-years) in the didanosine 500 mg, didanosine 200 mg, and zidovudine groups (zidovudine vs. didanosine 500 mg, relative risk 1.28, 95% confidence interval, 0.88-1.86, p = 0.19; didanosine 200 vs. 500 mg, relative risk 1.24, 95% confidence interval, 0.85-1.79, p = 0.26). In subjects with a baseline CD4 count of 100/mm3 or more, the primary end point rates were 8, 29, and 25 (per 100 person-years) in the didanosine 500 mg, didanosine 200 mg, and zidovudine groups, respectively (zidovudine vs. didanosine 500 mg, relative risk 2.96, 95% confidence interval 0.91-9.62, p = 0.07). No difference was seen in survival. In the didanosine 500 mg group, more patients had a 50% increase in CD4 cells (10% vs. 1% in zidovudine group, p = 0.01) and an increase of > or = 2.5 kg in body weight (2% versus 3%). Fatal pancreatitis developed in one patient assigned to didanosine 500 mg and in one to zidovudine. Our data suggest that switching from zidovudine to currently recommended doses of didanosine in subjects with ARC or AIDS who show evidence of clinical and laboratory disease progression can be associated with improvements in clinical outcome as well as in surrogate markers of HIV disease progression. This effect tended to be greater among individuals with higher CD4 counts (>100/mm3).

Identifying high risk patients for Staphylococcus aureus infections: skin and soft tissue infections

Staphylococcus aureus is the causative organism for many skin and soft tissue (SST) infections. Some SST infections have severe systemic complications, such as bacteraemia and sepsis. S. aureus is the cause of 75% of primary pyodermas. Pre-existing conditions, like tissue injury (ulcers, wounds) or tissue inflammation (exudative dermatitis), and also underlying disorders (such as poorly controlled insulin-dependent diabetes mellitus or cancer) are some of the risk factors for secondary infection with S. aureus. In S. aureus-infected primary skin disorders (impetigo, recurrent eczema), 2% mupirocin ointment has proved effective in several clinical trials. S. aureus is responsible for 25% of all burn-wound infections, and burn units could be the point of entry and source of spread of methicillin-resistant S. aureus infection outbreaks. Mupirocin (2% ointment) has also proven effective for topical treatment of these infections. Pressure sores develop in 6% of all patients admitted to acute and chronic health care institutions. An average of three aerobic species (including S. aureus) plus one anaerobic species are isolated when infected. Infectious complications are responsible for 60-80% of all intravenous drug user (IVDU) hospital admissions, 5-20% being due to S. aureus infective endocarditis (IE). The origin of IE in IVDUs is probably the skin. Data from a Collaborative Spanish Study of IVDU infectious complications (including more than 10,000 episodes) are discussed.

Prognostic factors influencing the outcome in pneumocystis carinii pneumonia in patients with AIDS

BACKGROUND

Studies attempting to identify the prognostic factors that influence the outcome of Pneumocystis carinii pneumonia (PCP) in patients with AIDS using a multivariate analysis are few. In order to identify those prognostic factors amenable to medical intervention, univariate and multivariate analyses were performed on 102 patients with AIDS suffering a first episode of PCP.

METHODS

One hundred and two consecutive patients with AIDS (51% drug abusers, 45% homosexuals, and 4% with other HIV risk factors) admitted to our institution between 1986 and 1989 whose respiratory infection was diagnosed by bronchoalveolar lavage were studied prospectively.

RESULTS

The overall mortality was 28%, rising to 79% in those patients who required mechanical ventilation. According to univariate analysis the following variables were related to a poor prognosis: age > 35 years; risk factor for HIV infection other than drug abuse; and AIDS diagnosis confirmed before 1988; PaO2 < 8 kPa at admission; severe acute respiratory failure on admission (PaO2/FIO2 < 20 kPa); mechanical ventilation; antibiotic therapy for PCP other than trimethoprim-sulphamethoxazole; multiple microbial pulmonary infection; serum lactate dehydrogenase (LDH) > 22.5 mukat/l on admission; serum albumin level < 30 g/l. Multivariate analysis showed that only mechanical ventilation was independently associated with a poor outcome.

CONCLUSIONS

The mortality of AIDS patients presenting with a first episode of PCP before 1990 was high (28%). The main prognostic factor associated with poor outcome was the requirement for mechanical ventilation due to severe acute respiratory failure.