Efficacy of Prophylactic Antibiotics in Simple Knee Arthroscopy.

PURPOSE: To determine the association between the use of preoperative antibiotics and the risk of postoperative infection after simple knee arthroscopy. METHODS: The electronic medical records of a large integrated health care organization were used to identify patients who underwent simple knee arthroscopy between 2007 and 2012. Patient demographics, potential infection risk factors, and antibiotic administration data were extracted. Simple knee arthroscopy included debridement, meniscectomy, meniscus repair, synovectomy, microfracture, and lateral release. Complex knee arthroscopy, septic knees, and cases involving fractures were excluded. Deep infection was defined as a positive synovial fluid culture or signs and symptoms of infection and gross pus in the knee. Superficial infection was defined as clinical signs of infection localized to a portal site and treatment with an antibiotic. RESULTS: Of 40,810 simple knee arthroscopies, 32,836 (80.5%) received preoperative antibiotics and 7,974 (19.5%) did not. There were 25 deep infections in the antibiotic group (0.08%) and 11 in the no-antibiotics group (0.14%) (risk ratio = 0.55, 95% confidence interval: 0.27 to 1.12, P = .10). There were 134 superficial infections in the antibiotic group (0.41%) and 32 in the no-antibiotics group (0.40%) (risk ratio = 1.01, 95% confidence interval: 0.29 to 1.49, P = .93). CONCLUSIONS: In our large sample of patients who underwent simple knee arthroscopy, there was no association between preoperative antibiotic use and postoperative deep or superficial infection rates at the 95% confidence level (P = .05). There was an association between preoperative antibiotic use and a decreased deep infection rate at the P = .10 level. LEVEL OF EVIDENCE: Level IV, case series.

Multiple primary melanomas among 16,570 patients with melanoma diagnosed at Kaiser Permanente Northern California, 1996 to 2011.

BACKGROUND: Published rates of cutaneous multiple primary melanoma (MPM) vary widely. OBJECTIVE: We examined incidence of and risk factors associated with MPMs among Kaiser Permanente Northern California members. METHODS: We estimated MPM incidence among 16,570 patients with melanoma from 1996 through 2011. We compared characteristics between patients with MPMs and single primary melanomas and estimated crude and adjusted hazard ratios of MPMs using Cox models. RESULTS: In all, 15,448 patients had a single melanoma and 1122 had MPMs. Patients with MPMs were older and more often male, non-Hispanic white, and partnered. Subsequent primary melanomas were diagnosed after a mean of 3.83 (SD 3.61, median 2.82) years and were more likely in situ and thinner than initial tumors. The risk of a subsequent melanoma decreased from 2% in the first year after diagnosis to a stable approximately 1% rate through 15 years of follow-up. LIMITATIONS: We lacked data on some known melanoma risk factors and had small numbers of non-white patients and certain tumor subtypes. CONCLUSIONS: The risk of MPMs, although highest in the first year after diagnosis, remains stable thereafter. Those at highest risk of MPMs are older, male, white, and partnered. Clinicians should be aware of the rate of MPMs and recognize high-risk subgroups.

Antidepressants and testicular cancer.

PURPOSE: Re-examine association of fluoxetine and paroxetine with risk of testicular cancer noted in drug screening, with 4 years more follow-up and expanded study of these and other antidepressant drugs. METHODS: In the Kaiser Permanente Medical Care Program in Northern California, 906 men with testicular cancer diagnosed August 1996-December 2010 were compared with 38,253 matched controls with race/ethnicity recorded regarding receipt of antidepressant drugs at least 2 years before diagnosis or control index date. Analyses emphasized duration of use and histological subgroups. RESULTS: With control for race/ethnicity and use of other antidepressant drugs, odds ratios (OR) and 95 % confidence intervals (CI) for associations with testicular cancer were as follows: fluoxetine 1.22 (0.88-1.71), paroxetine 1.19 (0.78-1.83), and 1.21 (0.92-1.58) for all serotonin reuptake inhibitors. There was no statistically significant association with risk of all testicular cancers or their histological subtypes for any individual drug or for tricyclics or all antidepressants combined except for citalopram with all testicular cancers 2.55 (1.43-4.52) and those of mixed histology 4.36 (1.50-12.68) and nefazodone with embryonal cancers 9.79 (1.85-51.81). These could readily be chance findings in the context of the many analyses that were performed. Duration of use was not associated with risk of the drugs and drug groups with sufficient numbers of exposed cases for analysis. CONCLUSIONS: We found little evidence to support a testicular carcinogenic effect of fluoxetine, paroxetine, or other antidepressant drugs, but a weakly positive association is not ruled out. The signals in prior screening may have been due to chance and/or uncontrolled confounding.

Encephalopathy after whole-cell pertussis or measles vaccination: lack of evidence for a causal association in a retrospective case-control study.

BACKGROUND: Whole-cell pertussis (wP) and measles vaccines are effective in preventing disease but have also been suspected of increasing the risk of encephalopathy or encephalitis. Although many countries now use acellular pertussis vaccines, wP vaccine is still widely used in the developing world. It is therefore important to evaluate whether wP vaccine increases the risk of neurologic disorders. METHODS: A retrospective case-control study was performed at 4 health maintenance organizations. Records from January 1, 1981, through December 31, 1995, were examined to identify children aged 0 to 6 years old hospitalized with encephalopathy or related conditions. The cause of the encephalopathy was categorized as known, unknown or suspected but unconfirmed. Up to 3 controls were matched to each case. Conditional logistic regression was used to analyze the relative risk of encephalopathy after vaccination with diphtheria-tetanus-pertussis (DTP) or measles-mumps-rubella (MMR) vaccines in the 90 days before disease onset as defined by chart review compared with an equivalent period among controls indexed by matching on case onset date. RESULTS: Four-hundred fifty-two cases were identified. Cases were no more likely than controls to have received either vaccine during the 90 days before disease onset. When encephalopathies of known etiology were excluded, the odds ratio for case children having received DTP within 7 days before onset of disease was 1.22 (95% confidence interval [CI] = 0.45-3.31, P = 0.693) compared with control children. For MMR in the 90 days before onset of encephalopathy, the odds ratio was 1.23 (95% confidence interval = 0.51-2.98, P = 0.647). CONCLUSIONS: In this study of more than 2 million children, DTP and MMR vaccines were not associated with an increased risk of encephalopathy after vaccination.

Efficacy, immunogenicity and safety of heptavalent pneumococcal conjugate vaccine in low birth weight and preterm infants.

OBJECTIVE: To determine the efficacy, immunogenicity and safety of the heptavalent CRM197 pneumococcal conjugate vaccine (PCV) in low birth weight (LBW) and preterm (PT) infants against invasive pneumococcal disease caused by vaccine types. METHODS: In a randomized double blind trial of 37,868 infants given either PCV or meningococcal type C conjugate vaccine (MCV), 1756 infants <750 g <2500 g (LBW) and 4340 infants from 32 to <38 weeks old (PT) were identified. Risk of invasive pneumococcal disease in LBW and PT infants was compared with risk in normal birth weight (NBW) and full term (FT) infants. Local and systemic events observed within 48 h of recent vaccine were assessed by telephone interviews and similar comparisons made. Premature infant Emergency Department visits and hospitalization were also identified and compared with FT and NBW infants. RESULTS: Initiation of immunization and intervals between doses were similar for all groups. The risk ratio for invasive pneumococcal diseases for LBW infants compared with NBW infants was 2.6 (P = 0.03), and for PT compared with FT infants the risk ratio was 1.6 (P = 0.06). Vaccine efficacy for both groups was 100%. PCV was as immunogenic in LBW and PT as in NBW and FT infants. Fever and local events after PCV vaccination were similar when adjusted for clustering among multiple doses per child. When stratified for individual doses there was more redness and swelling for LBW infants and more swelling for PT infants after Dose 3. Isolated local and systemic reactions were more commonly seen with PCV than with MCV, a pattern similar to that in NBW and FT infants. Hospitalization rates were similar for PCV and MCV recipients. CONCLUSION: These data support the use of PCV in LBW infants and PT infants.