Referral Center In South Korea Research Articles

The Association Between Sputum Culture Conversion and Mortality in Cavitary Mycobacterium avium Complex Pulmonary Disease

The association between treatment outcome and the mortality of Mycobacterium avium complex (MAC) pulmonary disease (PD) with cavitary lesions is unclear. Here, we assessed the impact of culture conversion on mortality in patients with cavitary Mycobacterium avium complex pulmonary disease. Is the achievement of sputum culture conversion in MAC-PD with cavitary lesions associated with the prognosis? From 2002 to 2020, 351 patients with cavitary MAC-PD (105 with the fibrocavitary type and 246 with the cavitary nodular bronchiectatic type), who had been treated with a ≥6-month macrolide-containing regimen at a tertiary referral center in South Korea, were retrospectively enrolled in this study. All-cause mortality during the follow-up period was analyzed based on culture-conversion at the time of treatment completion. The cohort had a median treatment duration of 14.7 (interquartile range, IQR: 13.4-16.8) months. Of the 351 patients, 69.8% (245/351) achieved culture conversion, while 30.2% (106/351) did not. The median follow-up was 4.4 years (IQR: 2.3-8.3) in patients with culture conversion and 3.1 years (IQR: 2.1-4.8) in those without. For the patients with and without culture conversion, all-cause mortality was 5.3% vs. 35.8% (P<0.001), and the 5-year cumulative mortality was 20.0% vs. 38.4%, respectively. Cox analysis found that a lack of culture conversion was significantly associated with higher mortality (adjusted hazard ratio: 5.73; 95% confidence interval: 2.86-11.50). Moreover, the 2-year landmark analysis revealed a distinct impact of treatment outcome on mortality. The mortality rate of patients with cavitary MAC-PD who did not achieve culture conversion was significantly higher than that of those with culture conversion.

Comparison of treatment outcomes between intermittent and daily regimens in non-cavitary nodular bronchiectatic-type Mycobacterium avium complex pulmonary disease in relation to sputum smear results: a retrospective cohort study.

This study retrospectively analyzed the treatment outcomes of 110 patients with non-cavitary nodular bronchiectatic-type Mycobacterium avium complex pulmonary disease who received intermittent or daily treatment with a three-drug oral antibiotic regimen (i.e., a macrolide, ethambutol, and rifampin) at a tertiary referral center in South Korea. Among these patients, 36 had sputum smear positivity. Of these 36 patients, intermittent treatment led to a lower culture conversion rate than daily treatment [50.0% (8/16) vs 85.0% (17/20), P = 0.034].

Comparison of Treatment Outcomes of Cavitary Mycobacterium avium Complex Pulmonary Disease with Streptomycin or Amikacin Use.

The comparative outcomes of specific aminoglycosides in cavitary type (fibrocavitary or cavitary nodular bronchiectatic type) Mycobacterium avium complex (MAC) pulmonary disease (PD) are unelucidated. We investigated the treatment outcomes with streptomycin or amikacin inclusion in the treatment regimen. From 2006 to 2020, 168 patients with cavitary MAC-PD who received guideline-based therapy (a three-drug oral antibiotic regimen with macrolide, ethambutol, and rifampin with an injectable aminoglycoside) for ≥1 year at a tertiary referral center in South Korea were retrospectively enrolled. We compared the rates of the culture conversion achievement of patients with streptomycin or amikacin use. Of the 168 participants, 127 patients (75.6%) received streptomycin and 41 (24.4%) received amikacin (median [interquartile range] treatment duration of 17.6 [14.2 to 25.2] and 17.0 [14.0 to 19.4] weeks, respectively). The overall culture conversion rate at treatment completion was 75.6% (127/168), and the rates were similar for the streptomycin-treated and amikacin-treated groups (74.8% [95/127] and 78.0% [32/41], respectively; P = 0.674). A multivariate analysis revealed that the achievement of culture conversion did not differ significantly with streptomycin or amikacin use (adjusted odds ratio, 1.086; 95% confidence interval, 0.425 to 2.777). The rate of adverse events was similar in the two groups. In conclusion, in cavitary MAC-PD, treatment with streptomycin-containing and amikacin-containing regimens results in similar rates of culture conversion achievement. IMPORTANCE We found that among the participants with cavitary MAC-PD who received guideline-based treatment for ≥1 year, the selection of either streptomycin or amikacin in the treatment regimen led to similar rates of culture conversion at treatment completion. In addition, the adverse reaction development rate did not differ significantly for streptomycin and amikacin. These findings suggest that either streptomycin or amikacin can be selected for the treatment of MAC-PD, according to the physician's or patient's preference, such as the route of administration.

Treatment With Liposomal Irinotecan Plus Fluorouracil and Leucovorin for Patients With Previously Treated Metastatic Biliary Tract Cancer

The NIFTY trial demonstrated the benefit of treatment with second-line liposomal irinotecan (nal-IRI) plus fluorouracil (FU) and leucovorin (LV) for patients with advanced biliary tract cancer (BTC). To report the updated efficacy outcomes from the NIFTY trial with extended follow-up of 1.3 years with reperformed masked independent central review (MICR) with 3 newly invited radiologists. The NIFTY trial was a randomized, multicenter, open-label, phase 2b clinical trial conducted between September 5, 2018, and December 31, 2021, at 5 tertiary referral centers in South Korea. Patients with advanced BTC whose disease progressed while receiving first-line gemcitabine plus cisplatin with at least 1 measurable lesion per Response Evaluation Criteria in Solid Tumors, version 1.1, were eligible. Data analysis was completed on May 9, 2022. Patients were randomized 1:1 to receive LV, 400 mg/m2, bolus and FU, 2400 mg/m2, for a 46-hour infusion intravenously every 2 weeks with or without nal-IRI, 70 mg/m2, before LV intravenously. Patients were treated until disease progression or unacceptable toxic effects. Primary end point was progression-free survival (PFS) as assessed by MICR. Secondary end points were PFS as assessed by the investigator, overall survival, and objective response rate. A total of 178 patients (75 women [42.1%]; median [IQR] age, 64 [38-84] years) were randomly assigned, and 174 patients were included in the full analysis set (88 patients [50.6%] in the nal-IRI plus FU/LV group vs 86 patients [49.4%] in the FU/LV alone group). In this updated analysis, the median MICR-assessed PFS was 4.2 months (95% CI, 2.8-5.3) for the nal-IRI plus FU/LV group and 1.7 months (95% CI, 1.4-2.6) for the FU/LV alone group (hazard ratio, 0.61; 95% CI, 0.44-0.86; P = .004), in contrast to the 7.1 and 1.4 months reported in the previous study, respectively. The discordance rate for tumor progression date between the MICR and investigators was 17.8% (vs 30% in the previous study). The NIFTY randomized clinical trial demonstrated significant improvement in PFS with treatment with nal-IRI plus FU/LV compared with FU/LV alone for patients with advanced BTC after progression to gemcitabine plus cisplatin. The combination of nal-IRI plus FU/LV could be considered as a second-line treatment option for patients with previously treated advanced BTC. clinicaltrials.gov Identifier: NCT03524508.

Impact of Treatment on Long-Term Survival of Patients With Mycobacterium avium Complex Pulmonary Disease.

Whether antimicrobial treatment improves long-term survival in patients with Mycobacterium avium complex pulmonary disease (MAC-PD) is unclear. We analyzed survival in patients aged ≥18 years who were treated for MAC-PD at a tertiary referral center in South Korea between 1 January 2009 and 31 December 2020. Treatment exposure was divided into 4 time intervals: <6, ≥6 to <12, ≥12 to <18, and ≥18 months. Time-varying multivariable Cox proportional hazards models were used to calculate the all-cause mortality risk in each time interval. The model was adjusted for major clinical factors related to mortality including age, sex, body mass index, presence of cavities, erythrocyte sedimentation rate, positive acid-fast bacilli (AFB) smear, clarithromycin resistance, and comorbid conditions. A total of 486 patients treated for MAC-PD were included in the analysis. A significant inverse correlation was observed between mortality and duration of treatment (P for trend = .007). Long-term treatment (≥18 months) was significantly associated with reduced mortality (adjusted hazard ratio, 0.32 [95% confidence interval, .15-.71]). In subgroup analyses, patients with cavitary lesions (adjusted hazard ratio, 0.17 [95% confidence interval, .05-.57]) or positive AFB smears (0.13 [.02-.84]) at baseline maintained this significant inverse relationship between treatment duration and mortality. Long-term antimicrobial treatment should be actively considered in patients with progressive MAC-PD, especially in the presence of cavities or positive AFB smears indicative of high mycobacterial burden.

Radiologic Subtypes and Treatment Outcome of Unclassifiable Type Mycobacterium avium Complex Pulmonary Disease.

Although the "unclassifiable type" is categorized as one of the radiologic classifications in Mycobacterium avium complex (MAC) pulmonary disease (PD), there have been few studies of this type thus far. We aimed to investigate the radiologic subtypes and treatment outcome of unclassifiable type MAC-PD. Ninety-six patients with unclassifiable type MAC-PD who initiated a macrolide-containing regimen from 2001 to 2020 were identified at a tertiary referral center in South Korea. Among these 96 patients, 1-year culture conversion rate was analyzed for 48 patients who received standard treatment (three-drug oral-antibiotic combination with or without an injectable agent) for ≥ 1 year. The mean age of the 96 patients was 65.4 ± 10.8 years, and 72.9% of them were male. These patients were classified into four major radiologic subtypes; the most common subtype was the focal cavity subtype (n = 31, 32.3%), followed by the focal mass or nodule (n = 23, 24.0%), consolidation upon emphysema (n = 21, 21.9%), and bronchiolitis (n = 21, 21.9%) subtypes. For the 48 patients who received standard treatment for ≥ 1 year, the overall rate of culture conversion at 1-year was 93.8%. All patients in the focal cavity subtype and focal mass or nodule subtype categories achieved 1-year culture conversion. Additionally, 1-year culture conversion rate was 92.9% in consolidation upon emphysema subtype and 75.0% in bronchiolitis subtype. Unclassifiable type MAC-PD can be radiologically further categorized into four major radiologic subtypes. The treatment outcome of all of these subtypes seems to be favorable.

Clinical Outcome with Standard Regimen plus Clofazimine or Moxifloxacin in Cavitary Mycobacterium avium Complex Pulmonary Disease.

In this retrospective analysis including 173 patients in a tertiary referral center in South Korea, compared with the standard therapeutic regimen, clofazimine or moxifloxacin plus standard treatment regimen potentially did not induce a higher 1-year culture conversion rate in patients with Mycobacterium avium complex pulmonary disease who present with cavitary lesions (fibrocavitary or cavitary nodular bronchiectatic type).

Drug-level change and optimal dose adjustment of tacrolimus with the use of rifabutin for treating mycobacterial disease in solid organ transplant recipients.

Little is known about the change in drug level and the need for dose adjustment of calcineurin inhibitor when it is used with rifabutin in solid organ transplant (SOT) recipients. We aimed to analyze whether the drug level of tacrolimus significantly reduced after the use of rifabutin and to assess optimal adjustment of tacrolimus dose in SOT recipients. Of the SOT recipients in a tertiary referral center in South Korea in 2000-2019, 50 patients who maintained an unchanged dose of tacrolimus after the use of rifabutin for treating mycobacterial disease were enrolled. Their medical records were reviewed retrospectively. The mean age of the patients was 53.9±11.5years. The most commonly transplanted organ was the liver (66.0%). The most common indication of rifabutin use was for treating active tuberculosis (78.0%). After rifabutin initiation, the trough level of tacrolimus decreased significantly to the subtherapeutic range in 38 (76.0%) patients. The drug levels of these 38 patients dropped from 7.2 to 3.8ng/ml (p<.001) after rifabutin treatment. In these patients, the median 1.5-fold increase in the tacrolimus dose was required to restore the drug level to the within-therapeutic range. These findings indicate that careful tacrolimus drug-level monitoring and dose adjustment are necessary for most SOT recipients when rifabutin is administered for the treatment of mycobacterial disease.

MO341: Clinical Significance of Post-Operative Acute Kidney Disease After Non-Cardiac Surgery

Abstract BACKGROUND AND AIMS Acute kidney disease (AKD), the condition of which acute kidney injury (AKI) has not recovered, is being emphasized because it increases the risk of progression to chronic kidney disease (CKD). Post-operative AKI (PO-AKI) is a common clinical setting prone to develop AKI although information on post-operative AKD (PO-AKD) is lacking. We investigated characteristics of PO-AKD events after non-cardiac surgery. METHOD We performed a retrospective cohort study from a tertiary referral center in South Korea. The patients who underwent non-cardiac surgery (five departments: general surgery, gynaecology, urology, neurosurgery and orthopedic surgery) &amp;gt;1 h from 2014 to 2020 were enrolled. Patients having advanced CKD patients and those receiving nephrectomy were excluded. PO-AKI was defined as whether the KDIGO AKI criteria were satisfied within 7 days after surgery. PO-AKD was defined as a case of not recovering to &amp;lt;1.5× from baseline within 7 days of peak creatinine measurement after surgery among PO-AKI patients. The information of death event and initiation of renal replacement therapy were collected. RESULTS A total of 83 361 patients were enrolled and 4824 (5.8%) cases of AKI and 852 cases of critical AKI (1.0%) were occurred. Among PO-AKI patients, 321 (6.7%) patients were progressed to PO-AKD. Patients with PO-AKD had a higher blood pressure, a lower body mass index, more coronary artery disease, higher inflammatory markers and a higher proportion of hematuria compared with those with PO-AKI but recovered. They were younger and more women. Moreover, they had fewer comorbidities such as lower SPARK scores, lower proportions of diabetes mellitus, hypertension and malignancy, and better kidney function immediately before receiving surgery than the recovered group (Table 1). However, they tended to experience more critical AKI (critical AKI event among PO-AKI 157 patients, 48.9%; recovery 695 patients, 15.4%) and consequently showed a higher incidence of all-cause mortality (post-operative 1 year: PO-AKD 56 patients, 17.4%; recovery 606 patients, 13.5%; p = .055; post-operative 3 year: PO-AKD 126 patients, 39.3%; recovery 1496 patients, 33.2%; p = .032) and newly started of renal replacement therapy after surgery (PO-AKD 49 patients, 15.3%; recovery 136 patients, 3.0%, p &amp;lt;.001). CONCLUSION In this large-scale study, we found that 6.7% of PO-AKI patients progressed to PO-AKD. PO-AKD patients tended to experience more severe AKI and also be associated with worse patients and kidney outcomes compared with their pre-existing condition.

Treatment outcome of continuation of intravenous amikacin for Mycobacterium abscessus pulmonary disease with a persistent culture positivity after the treatment initiation

IntroductionWhether prolonged intravenous amikacin treatment would lead to better treatment results in patients with Mycobacterium abscessus subspecies abscessus (M. abscessus) pulmonary disease (PD) is unknown. We investigated the efficacy of continued amikacin treatment for the microbiological outcome of M. abscessus PD patients with persistent culture positivity after treatment initiation. MethodsWe retrospectively evaluated 62 patients with M. abscessus PD who were treated with intravenous amikacin and beta-lactams along with a macrolide-based regimen at 3 tertiary referral centers in South Korea. The intravenous antibiotic treatment duration was determined by the attending physician. ResultsThe median treatment durations with amikacin and beta-lactam in the 62 patients were 25.1 and 8.2 weeks, respectively. The overall microbiological cure rate was 29.0%. Among the 62 patients, 44 showed persistent culture positivity at 8 weeks after treatment with an amikacin-containing multidrug regimen. The median parenteral amikacin treatment duration after 8 weeks in these patients was 18.0 weeks. The conditional probability of microbiological cure with continuation of the amikacin-containing regimen in these patients was 18.2% (95% confidence interval 8.2–32.7). Additionally, the conditional probability of microbiological cure in the 34 patients with persistent culture positivity at 12 weeks was 8.8% (95% confidence interval 1.9–23.7). After 16 weeks, the conditional probability of microbiological cure decreased further, reaching 0% at 28 weeks after treatment initiation. ConclusionThe continuation of intravenous amikacin therapy was usually not followed by culture conversion in M. abscessus PD patients with persistent sputum culture positivity after treatment initiation.

Treatment outcomes of the interstitial lung disease subtype of unclassifiable type Mycobacterium avium complex pulmonary disease

BackgroundWe aimed to investigate treatment outcomes according to the presence or absence of cavitary lesions in patients with the interstitial lung disease (ILD) subtype of unclassifiable type Mycobacterium avium complex (MAC) pulmonary disease (PD). MethodsStudy subjects were enrolled at a tertiary referral center in South Korea from 2001 to 2020. Among patients with MAC-PD who had ILD as an underlying disease, 38 patients who were diagnosed with the ILD subtype of unclassifiable MAC-PD and who received treatment for ≥1 year were selected for this study. Treatment outcomes in terms of microbiological cure at 1 year were retrospectively analyzed for these patients. ResultsThe mean age of the patients was 64.4 ± 12.9 years, and 63.2% were male. The presence of cavitary lesions was noted in 68.4% (26/38) patients. A usual interstitial pneumonia pattern was the predominant type of ILD, which was identified in 26 (68.4%) patients. The overall 1-year microbiological cure rate of the 38 patients was 65.8% (25/38). Of the 26 patients with cavitary lesions, microbiological cure at 1 year was achieved in 14 patients (53.8%), which is significantly lower than that in patients without cavitary lesions (91.7%, 11/12, p = 0.030). ConclusionsA clear difference in treatment outcomes was noted in the ILD subtype of MAC-PD according to the presence or absence of cavitary lesions.

The Risk of Tuberculosis in Patients With Inflammatory Bowel Disease Treated With Vedolizumab or Ustekinumab in Korea.

The present study investigated the risk of active tuberculosis in patients with inflammatory bowel disease (IBD) treated with vedolizumab or ustekinumab, in actual clinical settings in a country with an intermediate tuberculosis burden. The medical records of 238 patients with IBD who received vedolizumab or ustekinumab were retrospectively reviewed at a tertiary referral center in South Korea. All patients had ≥ 3 months of follow-up duration and underwent a latent tuberculosis infection screening test before initiation of the administration of these drugs. Of the 238 patients enrolled, 181 had Crohn’s disease, and 57 had ulcerative colitis. During the median 18.7 months of follow-up, active tuberculosis did not develop in any patient treated with vedolizumab or ustekinumab. Therefore, we concluded that the risk of tuberculosis appears to be low in patients with IBD treated with vedolizumab or ustekinumab in South Korea.

Safety and Temporal Pattern of the Lymphocyte Count During Fingolimod Therapy in Patients With Multiple Sclerosis: Real-World Korean Experience.

Fingolimod (FTY) inhibits lymphocyte egress from lymphoid organs to cause lymphopenia, but the clinical implications of FTY-induced lymphopenia are not fully understood. We aimed to determine the frequency and severity of lymphopenia during FTY treatment among Korean patients with multiple sclerosis (MS), and its association with infections. We retrospectively reviewed the medical records of patients with MS treated using FTY from 12 referral centers in South Korea between March 2013 and June 2021. Patients were classified according to their nadir absolute lymphocyte count (ALC) during treatment: grade 1, 800-999/µL; grade 2, 500-799/µL; grade 3, 200-499/µL; and grade 4, <200/µL. FTY treatment was administered to 69 patients with a median duration of 18 months (range=1-169 months), with 11 patients being treated for ≥7 years. During FTY treatment, mean ALCs were reduced after the first month (653.0±268.9/µL, mean±standard deviation) (p<0.0001) and remained low during treatment lasting up to 84 months. During follow-up, 41 (59.4%) and 7 (10.1%) patients developed grade-3 and grade-4 lymphopenia, respectively. No significant difference was found in age at FTY initiation, sex, baseline ALC, body mass index, or prior disease-modifying treatment between patients with and without grade-4 lymphopenia. Infections were observed in 11 (15.9%) patients, and the frequencies of patients with and without grade-4 lymphopenia were similar. FTY treatment induced grade-4 lymphopenia in 10% of South Korean patients with MS, but did not appear to be associated with an increased infection risk.

Efficacy of Fluoroquinolones as Substitutes for Ethambutol or Rifampin in the Treatment of Mycobacterium avium Complex Pulmonary Disease According to Radiologic Types.

During the treatment of Mycobacterium avium complex pulmonary disease (MAC-PD), ethambutol or rifampin is often discontinued because of adverse events. This study investigated the treatment outcomes when broader-spectrum fluoroquinolones replace ethambutol or rifampin in MAC-PD treatment based on the radiologic type. From 2006 to 2019, patients who initiated standard treatment and whose treatment duration was ≥1 year were retrospectively identified at a tertiary referral center in South Korea, including 178 patients with cavitary disease (fibrocavitary and cavitary nodular bronchiectatic types) and 256 patients with the noncavitary nodular bronchiectatic (NC-NB) type. We compared the microbiologic cure at 1 year between the patients who maintained the initial regimen and those who replaced ethambutol or rifampin with fluoroquinolones (moxifloxacin or levofloxacin). The overall microbiologic cure rate of the 178 patients with cavitary disease was 71.3%. Among these, the microbiologic cure rates of the 16 patients who substituted fluoroquinolones for ethambutol were lower than those of the 156 patients who maintained three-drug oral antibiotics with aminoglycoside (37.5% versus 74.4%, respectively; P = 0.007), which was statistically significant in multivariate analysis. The outcomes of the six patients receiving fluoroquinolones as an alternative to rifampin were similar to that of those continuing the initial regimen. The microbiologic cure rate of the patients with the NC-NB type receiving daily or intermittent oral three-drug therapy was similar regardless of maintaining the initial therapy or replacing ethambutol or rifampin with fluoroquinolones. In conclusion, in cavitary MAC-PD, replacing ethambutol with fluoroquinolones resulted in inferior patient outcomes.

Primary Prophylaxis for Pneumocystis jirovecii Pneumonia in Patients Receiving Rituximab

Although previous studies suggested that rituximab increases the risk of Pneumocystis jirovecii pneumonia (PJP), it is uncertain whether its primary prophylaxis for PJP is justified. Does the benefit of primary prophylaxis for PJP in patients receiving rituximab treatment outweigh the potential risk of the prophylaxis? This retrospective study included 3,524 patients (hematologic diseases, 2,500; rheumatic diseases, 559; pre/post-solid organ transplantation, 465) first exposed to rituximab between 2002 and 2018 in a tertiary referral center in South Korea. Patients were classified into a control group (n= 2,523) and a prophylaxis group (n= 1,001) according to the administration of prophylactic trimethoprim-sulfamethoxazole (TMP-SMX) during the first 28days after the start of rituximab (intention-to-treat analysis). In addition, exposure to TMP-SMX was examined as a time-varying variable (time-varying analysis). The primary outcome was the prophylactic effect of TMP-SMX on the 1-year incidence of PJP. Inverse probability of treatment weights was applied to minimize the baseline imbalance. The secondary outcome included the incidence of adverse drug reactions (ADRs) related to TMP-SMX. Over 2,759.9 person-years, 92 PJP infections occurred, with a mortality rate of 27.2%. The prophylaxis group showed a significantly lower incidence of PJP (adjusted subdistribution hazard ratio, 0.20 [95%CI, 0.10-0.42]) than the control group. This result was consistent with the results of time-varying analysis, in which only one PJP infection occurred during TMP-SMX administration (adjusted subdistribution hazard ratio, 0.01 [0.003-0.16]). The incidence of ADRs related to TMP-SMX was 18.1 (14.6-22.2)/100 person-years, and most were of mild to moderate severity. On the basis of 10 severe ADRs, the number needed to harm was 101 (61.9-261.1), whereas the number needed to prevent one PJP infection was 32 (24.8-39.4). TMP-SMX prophylaxis significantly reduces PJP incidence with a tolerable safety profile in patients receiving rituximab treatment.

Redevelopment after spontaneous sputum conversion in noncavitary nodular bronchiectatic Mycobacterium avium complex lung disease

BackgroundAlthough spontaneous sputum conversion can occur in noncavitary nodular bronchiectatic (NC-NB) Mycobacterium avium complex lung disease (MAC-LD), little is known about redevelopment after spontaneous conversion. We investigated the redevelopment phenomenon after spontaneous sputum conversion in patients with NC-NB MAC-LD. Material and methodsAmong patients diagnosed with NC-NB MAC-LD between 2000 and 2013, 140 patients who experienced spontaneous sputum conversion, and whose follow-up duration after conversion was ≥6 months, were enrolled at a tertiary referral center in South Korea. Their medical records were retrospectively reviewed. ResultsOf the 140 patients, 34 (24.3%) underwent redevelopment during the median follow-up period of 71.0 months (interquartile range [IQR], 58.8–87.5). Redevelopment occurred at a median interval of 25.0 months (IQR, 11.5–41.8) after spontaneous sputum conversion. The mean age of the 34 patients with redevelopment was 63.6 years, and 73.5% were women. No statistically significant differences in clinical characteristics were noted between the 34 patients with redevelopment and those with persistent conversion. Among the 34 patients with redevelopment, 6 received treatment at a median interval of 8 months (IQR, 1.5–16.8) after redevelopment. No significant differences in clinical characteristics were noted between the six treated and 28 untreated patients. ConclusionAt least approximately 24% of patients with spontaneous sputum conversion in NC-NB MAC-LD had redevelopment, and a portion of them required treatment. These findings suggest that long-term follow-up is necessary for patients with NC-NB MAC-LD, even those who experience spontaneous sputum conversion.

Cognitive trajectories of patients with focal \xdf-amyloid deposition

BackgroundThe presence of ß-amyloid (Aß) in the brain can be identified using amyloid PET. In clinical practice, the amyloid PET is interpreted based on dichotomous visual rating, which renders focal Aß accumulation be read as positive for Aß. However, the prognosis of patients with focal Aß deposition is not well established. Thus, we investigated cognitive trajectories of patients with focal Aß deposition.MethodsWe followed up 240 participants (112 cognitively unimpaired [CU], 78 amnestic mild cognitive impairment [aMCI], and 50 Alzheimer’s disease (AD) dementia [ADD]) for 2 years from 9 referral centers in South Korea. Participants were assessed with neuropsychological tests and 18F-flutemetamol (FMM) positron emission tomography (PET). Ten regions (frontal, precuneus/posterior cingulate (PPC), lateral temporal, parietal, and striatum of each hemisphere) were visually examined in the FMM scan, and participants were divided into three groups: No-FMM, Focal-FMM (FMM uptake in 1–9 regions), and Diffuse-FMM. We used mixed-effects model to investigate the speed of cognitive decline in the Focal-FMM group according to the cognitive level, extent, and location of Aß involvement, in comparison with the No- or Diffuse-FMM group.ResultsForty-five of 240 (18.8%) individuals were categorized as Focal-FMM. The rate of cognitive decline in the Focal-FMM group was faster than the No-FMM group (especially in the CU and aMCI stage) and slower than the Diffuse-FMM group (in particular in the CU stage). Within the Focal-FMM group, participants with FMM uptake to a larger extent (7–9 regions) showed faster cognitive decline compared to those with uptake to a smaller extent (1–3 or 4–6 regions). The Focal-FMM group was found to have faster cognitive decline in comparison with the No-FMM when there was uptake in the PPC, striatum, and frontal cortex.ConclusionsWhen predicting cognitive decline of patients with focal Aß deposition, the patients’ cognitive level, extent, and location of the focal involvement are important.

Cavity formation and its predictors in noncavitary nodular bronchiectatic Mycobacterium avium complex pulmonary disease.

The temporal dynamics of cavity formation in patients with the noncavitary nodular bronchiectatic (NC-NB) form of Mycobacterium avium complex pulmonary disease (MAC-PD) have not yet been well described. We aimed to investigate the development of new cavities in the NC-NB form of MAC-PD. Of the patients diagnosed with NC-NB-type MAC-PD between 2002 and 2013 and followed-up until July 2018at a tertiary referral center in South Korea, we identified 589 patients who underwent follow-up chest computed tomography at least once after the diagnosis and retrospectively analysed their medical records. The patients' mean age was 62.0 years, 64.7% were women. During the median follow-up of 3.8 years (interquartile range [IQR] 1.7-5.9), new cavity formation was noted in 51 (8.7%) patients. The median interval between the diagnosis of NC-NB MAC-PD and cavity formation was 3.7 years (IQR 1.8-5.4), with a constant occurrence over time. The Cox regression analysis showed that a history of pulmonary tuberculosis (adjusted hazard ratio [HR] 1.85; 95% confidence interval [CI] 1.06-3.23; P=0.030) and M. intracellulare as the causative organism (adjusted HR 2.03; 95% CI 1.15-3.59; P=0.014) were independently associated with new cavity formation. New cavity formation was noted in 8.7% of the patients with NC-NB MAC-PD in approximately 4 years after diagnosis, particular in those infected with M. intracellulare and those with a previous history of tuberculosis.

Fit-failure rate associated with simulated reuse and extended use of N95 respirators assessed by a quantitative fit test.

We quantitatively assessed the fit failure rate of N95 respirators according to the number of donning/doffing and hours worn. Experimental study. A tertiary-care referral center in South Korea. In total, 10 infection control practitioners participated in the fit test. The first experiment comprised 4 consecutive 1-hour donnings and fit tests between each donning. The second experiment comprised 2 consecutive 3-hour donnings and fit tests between each donning. The final experiment comprised fit tests after an 1-hour donning or a 2-hour donning. For 1-hour donnings, 60%, 70%, and 90% of the participants had fit failures after 2, 3, and 4 consecutive donnings, respectively. For 3-hour donnings, 50% had fit failure after the first donning and 70% had failures after 2 consecutive donnings. All participants passed the fit test after refitting whenever fit failure occurred. The final experiment showed that 50% had fit failure after a single use of 1 hour, and 30% had fit failure after a single use of 2 hours. High fit-failure rates were recorded after repeated donning and extended use of N95 respirators. Caution is needed for reuse (≥1 time) and extended use (≥1 hour) of N95 respirators in high-risk settings such as those involving aerosol-generating procedures. Although adequate refitting may recover the fit factor, the use of clean gloves and strict hand hygiene afterward should be ensured when touching the outer surfaces of N95 respirators for refitting.

Respiratory Viruses in Acute Exacerbations of Bronchiectasis.

BackgroundBacterial infections are well known factors underlying acute exacerbations in bronchiectasis. However, viral infections may also contribute to acute exacerbations. We aimed to assess the rate of viral detection in acute exacerbations of bronchiectasis, and the associated clinical factors.MethodsDiagnostic tests for viral and bacterial etiologies were performed in 792 patients with bronchiectasis who visited the emergency room or the respiratory care inpatient unit in a tertiary referral center in South Korea. All patients were diagnosed with bronchiectasis by chest computerized tomography and were prescribed antibiotics for a minimum of 3 days.ResultsViral pathogens were detected in 202 of the 792 enrolled patients (25.5%). The most common viral pathogen isolated was influenza A virus (24.8%), followed by rhinovirus (22.4%), influenza B virus (9.8%), respiratory syncytial virus B (8.9%), and human metapneumovirus (6.1%). In 145 patients, a viral, but not bacterial, pathogen was detected, whereas no pathogens were found in 443 patients with exacerbations. Multivariable analysis revealed that female sex and chronic heart disease as a comorbidity were positively associated with viral detection in acute exacerbations of patients with bronchiectasis, whereas the presence of radiographic infiltration was negatively associated.ConclusionRespiratory viruses were identified in approximately 25% of the acute exacerbations observed among patients with bronchiectasis. Of the viruses detected, influenza viruses and rhinovirus made up over 50%. More attention to viruses as possible causative pathogens for acute deteriorating symptoms in patients with bronchiectasis is warranted.