The gamma gap and all-cause mortality risk: considerations of physical activity

Low Serum Total Protein at Admission Predicts in-Hospital Mortality Among General Inpatients: Historical Cohort Study

Purpose

Low total protein (TP) is associated with mortality among patients with specific diseases, but its association was uncertain among general patients. We evaluated the effects of low TP on in-hospital mortality among general inpatients.

Patients and Methods

We used data from the Japan Adverse Drug Events study series. We enrolled adult inpatients (≥ 16 years) admitted to a tertiary care hospital between September 1 and November 30, 2013. We excluded patients with multiple myeloma, pregnant women, and bone marrow graft donors. Patient data were extracted from electronic medical records. All patients were stratified into those with and without malignancy and divided into the low and normal TP groups. Low TP was defined as < 6.5 g/dL. We compared the in-hospital mortality of the low and normal TP groups stratified by the presence of malignancy.

Results

Among the 2235 enrolled patients (mean age, 67.8 years), the TP value was lower in 516 patients with malignancy than in 1719 patients without malignancy (6.6 g/dL vs 6.8 g/dL, P = 0.0002). Among patients without or with malignancy, 27% (462/1719) and 35% (183/516) were in the low TP group, respectively. Mortality was higher in the low TP group among patients without malignancy (23.2% vs 10.2%, P < 0.0001). Likewise, among patients with malignancy, mortality was higher in the low TP group (34.7% vs 11.3%, P = 0.0029). The adjusted hazard ratio of the low TP group was 1.75 (95% confidence interval, 1.04–2.96) in patients without malignancy and 2.45 (95% confidence interval, 1.12–5.37) in patients with malignancy, but the interaction was not significant (P = 0.23).

Conclusion

Low TP values were associated with higher in-hospital mortality among general inpatients, and this association was observed among patients with and those without malignancy. Routinely measured TP should be utilized to risk stratification on admission.

Independent associations between sleep duration, gamma gap, and cognitive function among older adults: Results from the NHANES 2013-2014

This study examined whether gamma gap mediated the association between sleep and cognitive function. Data from NHANES 2013-2014 were used. Three tests were used to measure cognitive function. Sleep was measured by three single questions. Gamma gap was calculated by subtracting albumin from total protein. Participants were 1392 older adults (53.2% females). Approximately 12% reported being told having sleep disorder, 1/3 reported having trouble sleeping, 25.9% had short sleep, and 12.5% had long sleep. Sleep disorders and sleep quality were not associated with cognitive function. Long sleep duration was an independent risk factor of reduced cognitive function on immediate recall, delayed recall, and executive function. Elevated gamma gap was also an independent risk factor of lower cognitive function. In a representative sample of older adults in the US, gamma gap and sleep duration were independent predictors of cognitive function. This study highlights the need for sleep assessment among older adults.

Blurry Vision as a Presentation of Waldenström's Macroglobulinemia: A Case Report With Review of Current Management

A patient was diagnosed with Waldenström’s macroglobulinemia (WM) after the initial findings of anemia and ophthalmological findings of retinal hemorrhage. Upon further workup, the patient was found to have an IgM predominant monoclonal gammopathy on serum protein electrophoresis (SPEP) and urine protein electrophoresis (UPEP). This highlights the need for open communication between different specialties, streamlining rapid and accurate diagnosis. Also highlighted are the unique pathophysiological changes involved in the development of WM. A patient’s primary complaint was blurry vision. After the patient was noted to have a monoclonal gammopathy on SPEP, bone marrow biopsy was performed. The bone marrow biopsy findings were consistent with lymphoplasmacytic lymphoma (LPL). The patient received plasmapheresis and chemotherapy. The disease course is described. The patient saw rapid improvement in all lab abnormalities after the beginning of the appropriate therapy of plasmapheresis and chemotherapy. Remission is common with WM. Regular follow-up with this patient is important.

The Gamma Gap Predicts All-Cause Mortality in Chronic Dialysis Patients

Introduction:

The gamma gap (γ-gap) represents the total serum protein concentration minus the albumin concentration. The main aim of this study was to test whether the gamma gap is a predictor of mortality and whether it is associated with other predictors of mortality in chronic hemodialysis patients (CHPs).

Materials and Methods:

We studied a cohort of 100 CHPs with a mean age of 59 ± 12.3 years with duration of dialysis 6.5 ± 4.7 years. Serum proteins were determined by electrophoresis. The association of the gamma gap with serum C-reactive protein (CRP), fibrinogen and albumin concentration was evaluated for correlation. Cox regression analysis was used to identify the predictors of mortality.

Results:

The γ-gap correlates positively with CRP (r = 0.247, P = 0.013) and fibrinogen (r = 0.239, P = 0.016), and inversely with albumin (r = -0.430, P < 0.0001). The regression coefficients (b) and Exp (b) hazard ratio coefficients of covariates in Cox-regression survival analysis in all-cause outcomes were: b = 0.1486, Exp (b) = 1.1602 (P < 0.0001); b = 0.0655, Exp (b) = 1.0677 (P < 0.0015) and b = -0.118, Exp (b) = 0.8887 (P < 0.0009), for γ-gap, CRP and albumin, respectively.

Conclusions:

In patients on chronic hemodialysis, the gamma gap, along with serum albumin and CRP levels, is an independent predictor of mortality. Gamma gap levels correlate directly with serum CRP and fibrinogen levels and inversely with serum albumin levels.

Gamma gap thresholds and HIV, hepatitis C, and monoclonal gammopathy

BACKGROUND

An elevated gamma gap (>4 g/dL), the difference between serum total protein and albumin, can trigger testing for chronic infections or monoclonal gammopathy, despite a lack of evidence supporting this clinical threshold.

METHODS

Using the National Health and Nutrition Examination Survey (NHANES) 1999-2014, gamma gap was derived in three subpopulations based on availability of testing for human immunodeficiency virus (HIV; N = 25,680), hepatitis C (HCV; N = 45,134), and monoclonal gammopathy of unknown significance (MGUS; N = 6,118). Disease status was confirmed by HIV antibody and Western blot, HCV RNA test, or electrophoresis with immunofixation. Sensitivity, specificity, and likelihood ratios were calculated for different gamma gap thresholds. Area under the curve (AUC) was used to assess performance and cubic splines were used to characterize the relationship between the gamma gap and each disease.

RESULTS

Mean gamma gaps of participants with HIV, HCV, or MGUS ranged from 3.4-3.8 g/dL. The AUC was 0.80 (95%CI: 0.75,0.85) for HIV, 0.74 (0.72,0.76) for HCV, and 0.64 (0.60,0.69) for MGUS. An elevated gamma gap of over 4 g/dL corresponded to sensitivities of 39.3%, 19.0%, and 15.4% and specificities of 98.4%, 97.8%, and 95.4% for HIV, HCV, and MGUS, respectively. A higher prevalence of all three diseases was observed at both low and high gamma gaps.

DISCUSSION

An elevated gamma gap of 4 g/dL is insensitive for HIV, HCV, or MGUS, but has a high specificity for HIV and HCV, suggesting that the absence of an elevated gamma gap does not rule out HIV, HCV, or MGUS. Conversely, an elevated gap may justify further testing for HIV and HCV, but does not justify electrophoresis in the absence of additional clinical information.

Physical Activity and Cognitive Function among Older Adults with an Elevated Gamma Gap

OBJECTIVE

An elevated gamma gap is indicative of high serum concentrations of globulin proteins, some of which elicit acute inflammatory responses. An impaired cognitive function has been linked to central and peripheral inflammation, while exercise is associated with protective, anti-inflammatory benefits. In this study, we evaluated whether the gamma gap is associated with cognitive function among older adults and whether physical activity is favorably associated with cognitive function among those with an elevated gamma gap.

MATERIALS AND METHODS

Data from the 1999-2002 National Health and Nutrition Examination Survey (NHANES) were used to identify 2,352 older adults aged between 60 and 85 years. The gamma gap was evaluated by subtracting albumin from total protein, i.e., gamma gap = total protein (g/dL) - albumin (g/dL). Those at or above 3.1 g/dL (31.0 g/L) were considered to have an elevated gamma gap. The Digit Symbol Substitution Test (DSST) was used to assess cognitive function tasks of pairing and free recall among participants. Participants were asked open-ended questions about participation in leisure-time physical activity over the previous 30 days.

RESULTS

Those with an elevated gamma gap (DSST, 44.8) had a lower cognitive function score when compared to those without an elevated gamma gap (DSST, 50.1) (p < 0.001). After adjustments, and among those with an elevated gamma gap, those meeting the moderate-to-vigorous intensity physical activity (MVPA) guidelines (vs. not meeting them) had a DSST score of 6.42 units higher (β = 6.42, 95% CI 3.85-8.99, p < 0.001).

CONCLUSION

In this national sample of older adults, the gamma gap was associated with cognitive function, and among those with an elevated gamma gap, meeting the physical activity guidelines was associated with a higher cognitive function. Relevant clinical implications are discussed, as the gamma gap may be predictive of the risk for early mortality and reduced quality of life. Experimental work is needed to investigate whether physical activity training programs are effective in reducing an elevated gamma gap and preserving optimal cognitive functioning among at-risk individuals.

The gamma gap predicts 4-year all-cause mortality among nonagenarians and centenarians

Recent studies have revealed the prognostic role of the gamma gap, the total serum proteins concentration minus the albumin concentration, for predicting all-cause mortality among adults. This study aims to investigate the relationship between the gamma gap and all-cause mortality among nonagenarians and centenarians via a secondary data analysis of a prospective observational study. The analysis included 801 participants (260 men and 541 women, mean age: 93.7 ± 3.5 years), 46 of which were lost at the 4-year follow-up. The mean gamma gap was 2.7 ± 0.5 g/dl. After adjusting for relevant confounders, the gamma gap was significantly associated with 4-year all-cause mortality (hazard ratio [HR] per 1-SD = 1.22, 95% confidential interval [CI]: 1.12–1.78). Using different cut-off points, the elevated gamma gap could be defined as ≥2.9, 3.0, 3.1, or 3.2 g/dl. The relevant HRs and 95% CIs of the elevated gamma gap for predicting mortality were 1.27 (1.12–1.90), 1.29 (1.03–1.78), 1.21 (1.23–1.66), and 1.26 (1.09–1.69), respectively. In conclusion, the gamma gap is an independent prognostic factor for long-term mortality in nonagenarians and centenarians. A value greater than or equal to 3.1 g/dl may define an elevated gamma gap, but further studies are required.

Mid-arm muscle circumference as a substantial factor against mortality among people with elevated gamma gaps

Gamma gap is the difference in total serum proteins and albumin and an elevated gamma gap is related to infections, malignancy, and rheumatic diseases. An elevated gamma gap is also associated with higher mortality due to the correlation with inflammatory status. The study aimed to utilize mid-arm muscle circumference (MAMC) to assist in predicting all-cause mortality, cancer mortality, and cardiovascular mortality in people with elevated gamma gaps. Data were obtained from the third U.S. National Health and Nutrition Examination Survey (1988–1994), which contained 14,011 adults aged 20 to 90 years during up to 14.3 years of follow-up. The Primary analysis examined MAMC in tertiles and revealed the demographic and characteristics of the study population. Receiver operating characteristic curve analysis was used and the most suitable cut-off point of gamma gap was 3.65 g/dl. The secondary analysis employed Cox proportional hazards models stratified by age, gender and body mass index to evaluate the hazard ratios for all-cause mortality, cancer mortality, and cardiovascular mortality associated with the MAMC. As the MAMC tertiles increased in group with gamma gap ≥ 3.65 g/dl, individuals with elder age (60–90 years), normal range of body mass index (19–24.9 kg/m²), and male gender tended to have lower hazard ratios for all-cause mortality, cancer mortality, and cardiovascular mortality. These substantial findings indicate that higher MAMC may be a protective factor of all cause-mortality, cancer mortality, and cardiovascular mortality among older male with normal body mass index and elevated gamma gaps.