Validation of the multi-metric D-index change in the assessment of keratoconus progression

PURPOSE

To validate the effectiveness of the multi-metric D-index by Pentacam in detecting keratoconus (KC) progression.

MATERIALS AND METHODS

This was a retrospective study of KC patients at the Rabin Medical Center, Petah Tikva, Israel, during 2016-2018 with at least two corneal tomography examinations six months apart. Agreement between clinical diagnosis of progression (1.5D increase in mean keratometric value, 1D increase in Kmax, a 5% decrease in central corneal thickness (CCT), worsening of visual acuity by more than one line, or deterioration of manifest corneal astigmatism > 1.5D) and the D-index was evaluated. Receiver operating characteristic (ROC) analysis was used to find the D-index's optimal cutoff value to show progression.

RESULTS

We included KC eyes in the stable group (N = 7) and the progression group (N = 54). Patient demographics and tomographic parameters at baseline were similar between the groups. The D-index change was significantly higher in the progression group than in the stable group (median + 1 and 0.0, respectively, p = 0.024). Based on the ROC analysis, the optimal D-index cutoff change within at least six months was 0.32 (59.3% sensitivity and 100% specificity (area under the curve [AUC] = 0.771, Youden = 0.592). Subjects with a D-index change above this value had a 21.1-fold increase in odds for corneal ectasia progression requiring CXL (OR: 21.1, 95%CI 1.17-398.8, p = 0.038).

CONCLUSION

The multi-metric D-index can serve as a clinically feasible parameter to detect KC progression and guide patients' referral for further interventions.

High D-index during mobilization predicts poor mobilization of CD34+ cells after anti-lymphoma salvage chemotherapy

BACKGROUND

Performing stem cell collection after mobilization chemotherapy was a well-balanced strategy between anti-tumor effect and efficient collection of CD34+ cells, but deep and prolonged nadir exposed patients to risk of febrile neutropenia. Febrile neutropenia was known to be associated with lower yields of CD34+ cells, but quantitative data referring to association between yields of CD34+ cells and severity of neutropenia was lacking. We hypothesized that D-index, which was developed for quantitative evaluation of severity of neutropenia especially in the field of hematologic malignancies, could predict yields of CD34+ cells.

METHODS

We performed a single center, retrospective analysis of patients with relapsed or refractory aggressive lymphoma who were mobilized with ESHAP or modified ESHAP. We evaluated the association between yields of CD34+ cells at first apheresis and D-index.

RESULTS

Thirty-six patients were included, and we demonstrated that yields of CD34+ cells from patients with higher D-index were significantly lower than those from patients with lower D-index. Multivariate linear regression analysis and logistic regression analysis also demonstrated the significant predictive power of D-index. Further, D-index was significantly correlated to platelet count before starting mobilization chemotherapy. Platelet count was known to predict yields of CD34+ cells, and combination of platelet count and D-index could identify patients with lowest CD34+ yields.

CONCLUSION

D-index could predict yields of CD34+ cells and it seemed that its predictive power was not less than that of platelet count. Prospective studies including more heterogeneous patients were needed to validate our study.

A Powerful Nomogram Based on the Novel D-Index to Predict Prognosis After Surgical Resection of Hepatocellular Carcinoma

Purpose

Conventional staging and scoring systems such as the Tumor, Node, and Metastasis; Cancer of the Liver Italian Program; Barcelona Clinic Liver Cancer; and Okuda have failed to predict overall survival (OS) in patients with resected primary hepatocellular carcinoma. Thus, we aimed to establish a novel D-index and nomogram to improve prognostic accuracy.

Patients and Methods

We selected 396 patients who underwent liver resection between January 2007 and February 2015 at the First Affiliated Hospital of Wenzhou Medical University. These patients were randomly divided into the training and validation groups in a ratio of 7:3.

Results

We generated a nomogram using five independent risk factors, including the D-index (calculated by total bilirubin × tumor size/the ratio of fat-to-muscle area ^0.5) in the training set. The predictive performance of the nomogram was similar in both the training and validation cohorts according to the concordance index. The nomogram demonstrated the strongest predictive power for 1-year, 3-year, and 5-year OS, with the area under the receiving operating characteristic curve being 0.8486, 0.7785, and 0.752, respectively. The calibration curves exhibited stable capabilities in both cohorts. The stratification of the Kaplan-Meier curve was significant (P < 0.001).

Conclusion

The associated nomogram of the D-index demonstrated a powerful and accurate predictive ability for OS in patients with primary hepatocellular carcinoma.

D-index as a marker of bloodstream infections in patients with allogeneic hematopoietic stem cell transplantation

BACKGROUND

Neutropenia is a risk factor for development of infections; however, the direct effect of neutropenia on development of bloodstream infection (BSI) is not known. D-index, which is area between the neutrophil time curve and a neutrophil count of 0.5 × 10⁹ /L, incorporates the combined effect of severity and duration of neutropenia. We aimed to evaluate whether D-index can be used as a marker for BSI in patients with allogeneic stem cell transplantation.

METHOD

We conducted a retrospective cohort study of patients undergoing allogeneic stem cell transplantation between January 1, 2005, and September 30, 2015. The primary outcome measure was the development of BSI within 30 days of transplantation.

RESULTS

A total of 714 patients were included in the study of whom 101 developed BSI. Patients with BSI had a significantly higher median D-index value compared with patients who did not have BSI (4990 vs. 3570, P < .001). As a marker, the performance of the D-index was similar to that of the duration of profound neutropenia (P = .18) and significantly better than the total duration of neutropenia (P = .001).

CONCLUSION

The D-index performed better than the total duration of neutropenia as a marker for BSI in patients with allogeneic stem cell transplantation. There was no difference between D-index and, a more easily calculable indicator, duration of profound neutropenia.

Comparison of myelosuppression using the D-index between children and adolescents/young adults with acute lymphoblastic leukemia during induction chemotherapy

BACKGROUND

Adolescents and young adults (AYAs) with acute lymphoblastic leukemia (ALL) are more likely to have chemotherapy-related complications than children. In addition, several reports have shown that infections account for most of the therapy-related mortality during cancer treatment in AYAs. Thus, we hypothesized that chemotherapy-induced myelosuppression is more severe in AYAs than in children, and the state of neutropenia was compared between children and AYAs using the D-index, a numerical value calculated from the duration and depth of neutropenia.

PROCEDURE

This study retrospectively analyzed 95 patients newly diagnosed with ALL at our institution between 2007 and 2019. Of these, 81 were children (<15 years old) and 14 were AYAs (≥15 years old). The D-index and duration of neutropenia during induction chemotherapy for ALL were compared between children and AYAs.

RESULTS

The median D-index of children was significantly higher than that of AYAs (8187 vs 6446, respectively, P = .017). Moreover, the median duration of neutropenia was also significantly longer in children than in AYAs (24.0 days vs 11.5 days, respectively, P = .007).

CONCLUSION

Contrary to our expectations, myelosuppressive toxicity during induction chemotherapy for ALL was more severe in children than in AYAs.

Efficacy and safety of micafungin in empiric and D-index-guided early antifungal therapy for febrile neutropenia; A subgroup analysis of the CEDMIC trial

OBJECTIVES

The D-index is defined as the area over the neutrophil curve during neutropenia. The CEDMIC trial confirmed the noninferiority of D-index-guided early antifungal therapy (DET) using micafungin to empirical antifungal therapy (EAT). In this study, we evaluated the efficacy and safety of micafungin in these settings.

METHODS

From the CEDMIC trial, we extracted 67 and 113 patients who received micafungin in the DET and EAT groups, respectively. Treatment success was defined as the fulfilment of all components of a five-part composite end point. Fever resolution was evaluated at seven days after the completion of therapy.

RESULTS

The proportion of high-risk treatments including induction chemotherapy for acute leukemia and allogeneic hematopoietic stem cell transplantation was significantly higher in the DET group than in the EAT group (82.1% vs. 52.2%). The efficacy of micafungin was 68.7% (95%CI: 56.2-79.4) and 79.6% (71.0-86.6) in the DET and EAT groups, respectively. When we focused on high-risk treatments, the efficacy was 69.1% (55.2-80.9%) and 78.0% (65.3-87.7%), respectively (P = 0.30). There was no significant difference in any of the 5 components between the two groups.

CONCLUSIONS

The efficacy of micafungin in patients undergoing high-risk treatment was not strongly impaired in DET compared to that in EAT.

Impact of neutropenia evaluated in terms of the D-index on invasive fungal disease while on empiric or preemptive antifungal treatment strategy in the early phase after allogeneic hematopoietic stem cell transplantation

BACKGROUND

We retrospectively evaluated the association between the D-index, which reflects both the depth and duration of neutropenia, and proven/probable invasive fungal disease (IFD) early after allogeneic hematopoietic stem cell transplantation (HSCT) at our center (n = 394).

METHODS

The D-index was defined as the area over the neutrophil curve during neutropenia. The cumulative D-index from the start of neutropenia until the development of infection (c-D-index) was also evaluated as a real-time assessment of neutropenia.

RESULTS

There were 19 cases of early proven/probable IFD before and within 1 week after engraftment. Fifteen cases (78.9%) were seen as breakthrough infection while on empiric (n = 7), preemptive (n = 4) or prophylactic (n = 4) antifungal administration with mold-active agents. The c-D-index and lower performance status were identified as independent significant predictive factors for IFD. A receiver operating characteristic (ROC) curve analysis showed that the D-index and c-D-index were more accurate than the simple duration of neutropenia and as accurate as the duration of profound neutropenia for predicting IFD. The sensitivity, specificity, and positive and negative predictive values of the c-D-index using an appropriate cutoff (CO) value (10 644) determined by ROC curve analysis were 73.1%, 63.2%, 9.1%, and 97.9%, respectively. The advantage of the c-D-index to cumulative days of neutropenia in terms of positive and negative predictive values seemed to be small.

CONCLUSIONS

The appropriate CO value for the c-D-index for predicting IFD was as high as 10 644 in allogeneic HSCT with a more frequent use of empiric antifungal therapy. The c-D-index is useful for assessing the risk of breakthrough IFD.

The D-index is not correlated with invasive fungal infection during the early-post engraftment phase among allogeneic hematopoietic stem cell transplant recipients

The D-index assesses neutropenia dynamics. Prolonged neutropenia is a major risk for invasive fungal infection (IFI); we hypothesized that D-index is predictive of IFI risk. We retrospectively reviewed 789 adults who underwent allogeneic hematopoietic transplant (HSCT) from 1/1/2005 to 9/30/2015. Medical records were reviewed from transplant (D0) through Day 100. The D-index was calculated as area over the neutrophil curve until engraftment. 714 patients were included for analysis. Sixteen (2%) developed probable (11) or proven (5) IFI. Median time to IFI was 40 days (range 8-98) after HSCT. Groups with and without IFI did not differ significantly in duration of mild or profound neutropenia. Median D-index of those with IFI was 4293 days neutrophil/µl compared to 3590 days neutrophil/µl for those without IFI (P = 0.17). Patients who were neutropenic on D0 showed higher rates of IFI than those who were not (10/123 [8%] vs 6/591 [1%]; P < 0.001). Only 2% developed IFI, likely due to mold-active antifungal prophylaxis. The D-index was not significantly higher in those with IFI. Duration of profound neutropenia and neutropenia at D0 may be better markers for IFI among HSCT recipients during the first 30 and 100 days after transplant.

c-D-index is a risk factor for prolonged febrile neutropenia during chemotherapy in patients with acute myeloid leukemia

BACKGROUND

D-index is a recently established clinical tool for assessing neutropenia severity. This study examined whether the D-index can predict the onset of various infections in patients with febrile neutropenia (FN).

METHODS

We retrospectively investigated FN events in consecutive patients aged < 65 years who were treated for newly diagnosed acute myeloid leukemia at our institution. We collected data on all FN events during chemotherapy and evaluated the association of FN severity with infectious events.

RESULTS

This study included 35 patients (18 women and 17 men; median age, 51 years [range 18-65 years]) with 122 FN events. The response rate to induction chemotherapy was 60% (21/35), and all but one patient survived the treatment. The D-index did not predict FN onset. However, in multivariate analysis, high-dose cytarabine and total D-index were statistically significant explanatory factors for microbiological-proven infections. In addition, multivariate analysis showed that diabetes mellitus is the only risk factor for FN onset. Furthermore, older age, consolidation therapy, and cumulative D-index (c-D-index) were risk factors for prolonged FN. The FN period was the longest in patients with respiratory infections.

CONCLUSION

The D-index did not predict the onset of infection. However, FN duration might be prolonged during consolidation therapy in elderly patients with diabetes mellitus, and it is important to manage respiratory infections. These findings indicate the c-D-index is a useful tool to predict prolonged FN.

Impact of the D-index deduced from duration and intensity of neutropenia following chemotherapy on the risk of invasive fungal infection in pediatric acute myeloid leukemia

Pediatric patients with acute myeloid leukemia (AML) are at high risk of invasive fungal infection (IFI). In adult patients, the D-index, which reflects the duration and intensity of neutropenia, was reported as a predictive factor of IFI after induction therapy for AML. The aim of this study was to assess whether the D-index is a predictive factor for IFI in pediatric AML. We define the D-index as the area over the neutrophil curve during neutropenia. Ninety-two courses of chemotherapy performed for 24 consecutive patients with AML undergoing chemotherapy at Sapporo Hokuyu Hospital between April 2007 and March 2017 were analyzed. We also evaluated the utility of the cumulative D-index (c-D-index) from the start of neutropenia until the clinical manifestation of IFI in these patients. The D-index and c-D-index were compared between courses with and without IFI episodes. The median D-index and c-D-index in 6 courses with IFI episodes were 12,816 (range 9500-27,412) and 7250 (range 3987-16,273), respectively, which was not statistically higher than the median D-index [10,127 (range 3788-20,897)] in 86 courses without IFI episodes (P = 0.081 and P = 0.108, respectively). Unlike in adult cases, neither the D-index nor c-D-index reflected the risk of IFI in pediatric AML.

Impact of D-index and L-index on pulmonary infection in induction chemotherapy for acute lymphoblastic leukemia and lymphoblastic lymphoma

OBJECTIVES

The D-index and the L-index, calculated as the area over the neutrophil and lymphocyte curves, respectively, reflect both the intensity and duration of cytopenia. We, retrospectively, investigated the impact of these indexes on pulmonary infection (PI) in induction chemotherapy for acute lymphoblastic leukemia (ALL) and lymphoblastic lymphoma (LBL).

METHODS

We included 92 patients (ALL 83, LBL 9) from two institutions. We calculated the D-index and cumulative D-index until the development of PI (c-D-index), which enables real-time risk assessment for infection. We also calculated the L-index (35), defined as the area over the lymphocyte curve during lymphopenia (<700/µl) until day 35 and the cumulative-L-index until the development of PI (c-L-index).

RESULTS

Eight patients developed PI on day 20 (median). Two patients were strongly suspected to have bacterial pneumonia, and the others were suspected to have pulmonary fungal infection. The D-index and the L-index (35) in patients with PI were higher than those in patients without PI (7230 ± 4734 vs. 4519 ± 3416, P = 0.041 and 15 458 ± 5243 vs. 8920 ± 5901, P = 0.018), while the c-D-index and the c-L-index were not significantly different. Although the c-L-index did not have predictive value for PI, c-D-index, when treated as a dichotomous variable with a cutoff value of 5589 as determined by a receiver operating characteristic curve analysis, showed a significant difference between two groups (P = 0.045). This association became clearer when we focused on suspected pulmonary fungal infection.

DISCUSSION AND CONCLUSION

In induction chemotherapy for ALL/LBL, c-D-index with a cutoff value of 5589 might have predictive value for the development of PI.

Covariate-adjusted measures of discrimination for survival data

MOTIVATION

Discrimination statistics describe the ability of a survival model to assign higher risks to individuals who experience earlier events: examples are Harrell's C-index and Royston and Sauerbrei's D, which we call the D-index. Prognostic covariates whose distributions are controlled by the study design (e.g. age and sex) influence discrimination and can make it difficult to compare model discrimination between studies. Although covariate adjustment is a standard procedure for quantifying disease-risk factor associations, there are no covariate adjustment methods for discrimination statistics in censored survival data.

OBJECTIVE

To develop extensions of the C-index and D-index that describe the prognostic ability of a model adjusted for one or more covariate(s).

METHOD

We define a covariate-adjusted C-index and D-index for censored survival data, propose several estimators, and investigate their performance in simulation studies and in data from a large individual participant data meta-analysis, the Emerging Risk Factors Collaboration.

RESULTS

The proposed methods perform well in simulations. In the Emerging Risk Factors Collaboration data, the age-adjusted C-index and D-index were substantially smaller than unadjusted values. The study-specific standard deviation of baseline age was strongly associated with the unadjusted C-index and D-index but not significantly associated with the age-adjusted indices.

CONCLUSIONS

The proposed estimators improve meta-analysis comparisons, are easy to implement and give a more meaningful clinical interpretation.

D-index dose not predict the development of pulmonary infection in acute myeloid leukemia patients undergoing consolidation chemotherapy with high-dose cytarabine

The D-index is calculated as the area over the neutrophil curve during neutropenia. We investigated the impact of the D-index on pulmonary infection in 33 acute myeloid leukemia patients undergoing consolidation chemotherapy with high-dose cytarabine. There was no difference in the D-index between chemotherapies with and without pulmonary infection. The cumulative D-index (c-D-index) until the development of infection exceeded 4000 in four of five patients with pulmonary infection. Although there was no difference in the total D-index throughout the overall consolidation chemotherapy, the total D-index from induction to consolidation and the D-index at induction chemotherapy were higher in patients with pulmonary infection during consolidation than in those without it (P = 0.014 and 0.019, respectively). Our results showed that the cumulative effect of neutropenia might determine the risk of pulmonary infection in consolidation chemotherapy. We are planning a clinical trial of c-D-index-guided preemptive antifungal therapy.