The association of hospital spending intensity and cancer outcomes: a population-based study in an Asian country

BACKGROUND

Different results are reported for the relationship between regional variation in medical spending and disease prognosis for acute illness and for cancer. Our objective was to investigate the association between hospital medical care spending intensity and mortality rates in cancer patients.

METHODS

A total of 80,597 patients with incident cancer diagnosed in 2002 were identified from the National Health Insurance Research Database of Taiwan, Republic of China. The Cox proportional hazards model was used to compare the 5-year survival rates of patients treated at hospitals with different spending intensities after adjusting for possible confounding and risk factors.

RESULTS

After adjustment for patient characteristics, treatment modality, and hospital volume, an association was found between lower hospital spending intensity and poorer survival rates. The 5-year survival rate expressed by hazard ratios was 1.36 (95% confidence interval [CI]: 1.30-1.43, p < .001) for colorectal cancer, 1.18 (95% CI: 1.08-1.29, p < .001) for lung cancer, 1.13 (95% CI: 1.05-1.22, p = .002) for hepatoma, 1.16 (95% CI: 1.07-1.26, p < .001) for breast cancer, and 1.23 (95% CI: 1.10-1.39, p = .001) for prostate cancer.

CONCLUSION

Our preliminary findings indicate that higher hospital spending intensity was associated with lower mortality rates in patients being treated for lung cancer, breast cancer, colorectal cancer, prostate cancer, hepatoma, or head and neck cancer. The cancer stages were unavailable in this series, and more research linked with the primary data may be necessary to clearly address this issue.

Lens of controllable optical field with thin film metallic glasses for UV-LEDs

In the exposure process of photolithography, a free-form lens is designed and fabricated for UV-LED (Ultraviolet Light-Emitting Diode). Thin film metallic glasses (TFMG) are adopted as UV reflection layers to enhance the irradiance and uniformity. The Polydimethylsiloxane (PDMS) with high transmittance is used as the lens material. The 3-D fast printing is attempted to make the mold of the lens. The results show that the average irradiance can be enhanced by 6.5~6.7%, and high uniformity of 85~86% can be obtained. Exposure on commercial thick photoresist using this UV-LED system shows 3~5% dimensional deviation, lower than the 6~8% deviation for commercial mercury lamp system. This current system shows promising potential to replace the conventional mercury exposure systems.

The effect of individual and neighborhood socioeconomic status on gastric cancer survival

PURPOSE

Gastric cancer is a leading cause of death, particularly in the developing world. The literature reports individual socioeconomic status (SES) or neighborhood SES as related to survival, but the effect of both has not been studied. This study investigated the effect of individual and neighborhood SES simultaneously on mortality in gastric cancer patients in Taiwan.

MATERIALS AND METHODS

A study was conducted of 3,396 patients diagnosed with gastric cancer between 2002 and 2006. Each patient was followed for five years or until death. Individual SES was defined by income-related insurance premium (low, moderate, and high). Neighborhood SES was based on household income dichotomized into advantaged and disadvantaged areas. Multilevel logistic regression model was used to compare survival rates by SES group after adjusting for possible confounding factors.

RESULTS

In patients younger than 65 years, 5-year overall survival rates were lowest for those with low individual SES. After adjusting for patient characteristics (age, gender, Charlson Comorbidity Index Score), gastric cancer patients with high individual SES had 68% risk reduction of mortality (adjusted odds ratio [OR] of mortality, 0.32; 95% confidence interval [CI], 0.17-0.61). Patients aged 65 and above had no statistically significant difference in mortality rates by individual SES group. Different neighborhood SES did not statistically differ in the survival rates.

CONCLUSION

Gastric cancer patients aged less than 65 years old with low individual SES have higher risk of mortality, even under an universal healthcare system. Public health strategies, education and welfare policies should seek to correct the inequality in gastric cancer survival, especially in those with lower individual SES.

A model comparison study of the flowering time regulatory network in Arabidopsis

Background

Several dynamic models of a gene regulatory network of the light-induced floral transition process in Arabidopsis have been developed to capture the behavior of gene transcription and infer predictions based on experimental observations. It has been proven that the models can make accurate and novel predictions, which generate testable hypotheses.

Two major issues were addressed in this study. First, construction of dynamic models for gene regulatory networks requires the use of mathematic modeling that comprises equations of a large number of parameters. Second, the binding mechanism of the transcription factor with DNA is another factor that requires detailed modeling. The first issue was tackled by adopting an optimization algorithm, and the second was addressed by comparing the performance of three alternative modeling approaches, namely the S-system, the Michaelis-Menten model and the Mass-action model. The efficiencies of parameter estimation and modeling performance were calculated based on least square error (O(p)), mean relative error (MRE) and Akaike Information Criterion (AIC).

Results

We compared three models to describe gene regulation of the flowering transition process in Arabidopsis. The Mass-action model is the simplest and has the least parameters. It is therefore less computation-intensive with the smallest AIC value. The disadvantage, however, is that it assumes the system is simply a second order reaction which is not the case in our study. The Michaelis-Menten model also assumes the system is homogeneous and ignores the intracellular protein transport process. The S-system model has the best performance and it does describe the diffusion effects. A disadvantage of the S-system is that it involves the most parameters. The largest AIC value also implies an over-fitting may occur in parameter estimation.

Conclusions

Three dynamic models were adopted to describe the dynamics of the gene regulatory network of the flowering transition process in Arabidopsis. Based on MRE, the least square error and global sensitivity analysis, the S-system has the best performance. However, the fact that it has the highest AIC suggests an over-fitting may occur in parameter estimation. The result of this study may need to be applied carefully when modeling complex gene regulatory networks.

The combined effects of hospital and surgeon volume on short-term survival after hepatic resection in a population-based study

Background

The influence of different hospital and surgeon volumes on short-term survival after hepatic resection is not clearly clarified. By taking the known prognostic factors into account, the purpose of this study is to assess the combined effects of hospital and surgeon volume on short-term survival after hepatic resection.

Methods

13,159 patients who underwent hepatic resection between 2002 and 2006 were identified in the Taiwan National Health Insurance Research Database. Data were extracted from it and short-term survivals were confirmed through 2006. The Cox proportional hazards model was used to assess the relationship between survival and different hospital, surgeon volume and caseload combinations.

Results

High-volume surgeons in high-volume hospitals had the highest short-term survivals, following by high-volume surgeons in low-volume hospitals, low-volume surgeons in high-volume hospitals and low-volume surgeons in low-volume hospitals. Based on Cox proportional hazard models, although high-volume hospitals and surgeons both showed significant lower risks of short-term mortality at hospital and surgeon level analysis, after combining hospital and surgeon volume into account, high-volume surgeons in high-volume hospitals had significantly better outcomes; the hazard ratio of other three caseload combinations ranging from 1.66 to 2.08 (p<0.001) in 3-month mortality, and 1.28 to 1.58 (p<0.01) in 1-year mortality.

Conclusions

The combined effects of hospital and surgeon volume influenced the short-term survival after hepatic resection largely. After adjusting for the prognostic factors in the case mix, high-volume surgeons in high-volume hospitals had better short-term survivals. Centralization of hepatic resection to few surgeons and hospitals might improve patients’ prognosis.

Promising antimicrobial capability of thin film metallic glasses

Thin film metallic glasses (TFMGs) are demonstrated to exhibit excellent surface flatness, high corrosion resistance and satisfactory hydrophobic properties. Moreover, the antimicrobial and biocompatibility abilities of TFMGs are examined and the results are compared with the behavior of pure Ag and 316L stainless steel. Three TFMGs, Al48Ag37Ti15, Zr54Ti35Si11, and Zr59Ti22Ag19, are prepared by sputtering to assess the antimicrobial performance against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, which are the most common nosocomial infection pathogens. Experimental results show that the antimicrobial effect of the Al- or Ag-containing AlAgTi and ZrTiAg TFMGs is similar to that of the pure Ag coating. The ZrTiSi TFMG with no Ag or Al shows poor antimicrobial capability. The physical properties of highly smooth surface and hydrophobic nature alone are not sufficient to result in promising antimicrobial ability. The chemical metal ion release still plays a major role, which should be born in mind in designing biomedical devices.

Three-dimensional analysis of the surface registration accuracy of electromagnetic navigation systems in live endoscopic sinus surgery

BACKGROUND

Studies on the performance of surface registration with electromagnetic tracking systems are lacking in both live surgery and the laboratory setting. This study presents the efficiency in time of the system preparation as well as the navigational accuracy of surface registration using electromagnetic tracking systems.

METHODOLOGY

Forty patients with bilateral chronic paranasal pansinusitis underwent endoscopic sinus surgery after undergoing sinus computed tomography scans. The surgeries were performed under electromagnetic navigation guidance after the surface registration had been carried out on all of the patients. The intraoperative measurements indicate the time taken for equipment set-up, surface registration and surgical procedure, as well as the degree of navigation error along 3 axes.

RESULTS

The time taken for equipment set-up, surface registration and the surgical procedure was 179 +- 23 seconds, 39 +- 4.8 seconds and 114 +- 36 minutes, respectively. A comparison of the navigation error along the 3 axes showed that the deviation in the medial-lateral direction was significantly less than that in the anterior-posterior and cranial-caudal directions.

CONCLUSION

The procedures of equipment set-up and surface registration in electromagnetic navigation tracking are efficient, convenient and easy to manipulate. The system accuracy is within the acceptable ranges, especially on the medial-lateral axis.

A Hurst exponent estimator based on autoregressive power spectrum estimation with order selection

The discrete-time fractional Gaussian noise (DFGN) has been proven to be a regular process. According to Wold and Kolmogorov theorems, this process can be described as an autoregressive (AR) model of an infinite order. An estimator for the Hurst exponent based on autoregressive power spectrum estimation has been proposed, but without considering order selection. In this paper, six common order selection methods for the AR model were used to select appropriate orders of the AR model in order to raise the accuracy of estimating the Hurst exponent. Experimental results show that these six AR methods with considering order selection are more accurate than the original AR method without considering order selection.

Properties of lymphocyte chemotactic factor (lymphotactin) in thymus

Aqueous extracts of calf thymus from immunologically stimulated animals contain trypsin- and neuraminidase-labile macromolecules with molecular weights of less than 30,000 daltons which will specifically attract chemotactically lymphocytes. This activity we ascribe to "lymphotactin."

The combined effect of individual and neighborhood socioeconomic status on nasopharyngeal cancer survival

Background

The relationship between individual and neighborhood socioeconomic status (SES) and mortality rates in patients with nasopharyngeal carcinoma (NPC) is unknown. This population-based study aimed to examine the association between SES and survival of patients with NPC in Taiwan.

Materials and Methods

A population-based follow-up study was conducted of 4691 patients diagnosed with NPC between 2002 and 2006. Each patient was traced to death or for 5 years. Individual SES was defined by enrollee job category. Neighborhood SES was based on household income dichotomized into advantaged and disadvantaged areas. Cox proportional hazards model was used to compare the death-free survival rates between the different SES groups after adjusting for possible confounding factors and risk factors.

Results

In NPC patients below the age of 65 years, 5-year overall survival rates were worst for those with low individual SES living in disadvantaged neighborhoods. After adjusting for patient characteristics (age, gender, Charlson Comorbidity Index Score), NPC patients with low individual SES residing in disadvantaged neighborhoods were found to have a 2-fold higher risk of mortality than patients with high individual SES residing in advantaged neighborhoods. We found no significant difference in mortality rates between different SES groups in NPC patients aged 65 and above.

Conclusions

Our findings indicate that NPC patients with low individual SES who live in disadvantaged neighborhoods have the higher risk of mortality than their more privileged counterparts. Public health strategies and welfare policies would be well advised to try to offset the inequalities in health care and pay more attention to addressing the needs of this vulnerable group.

Long-term follow-up of central hepatocellular carcinoma in comparison with non-central hepatocellular carcinoma

BACKGROUND/AIMS

Multiple hepatic vessels and portal vessels are distributed in the central segments of the liver (segments IV, V and VIII). Due to its anatomical complexity, in centrally-located hepatocellular carcinoma (cHCC) it is theoretically not easy to reach a wide margin, as it is in non-central hepatocellular carcinoma (ncHCC) (segments II, III, VII and VIII). We compared their outcomes to see if cHCC has an inferior result than ncHCC.

METHODOLOGY

From August 2000 to July 2008, 213 HCC patients received curative-intended resection. Sixty-nine cHCC (group A) and 64 ncHCC (group B) received trisegmentectomy (include mesohepatectomy), bi-segmentectomy, mono-segmentectomy or subsegmentectomy. The outcomes were retrospectively analyzed.

RESULTS

The in-hospital mortality was 0% and 3.12% in groups A and B, respectively (p=0.55). The morbidity was 27.5% and 28.1% in groups A and B, respectively (p=0.23). The 1- and 3-year disease-free survival were 68%, 50% and 62%, 33% in groups A and B, respectively (p=0.39). The 1- and 3-year overall survival rates were 83%, 75% and 89%, 70% in groups A and B, respectively (p=0.91). Tumor size and numbers were significant factors for disease-free and overall survival.

CONCLUSIONS

cHCC treated by partial hepatectomy and mesohepatectomy has a comparable result to ncHCC. Mesohepatectomy is needed only in some selected patients.

Ab initio random structure search for 13-atom clusters of fcc elements

The 13-atom metal clusters of fcc elements (Al, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au) were studied by density functional theory calculations. The global minima were searched for by the ab initio random structure searching method. In addition to some new lowest-energy structures for Pd13 and Au13, we found that the effective coordination numbers of the lowest-energy clusters would increase with the ratio of the dimer-to-bulk bond length. This correlation, together with the electronic structures of the lowest-energy clusters, divides the 13-atom clusters of these fcc elements into two groups (except for Au13, which prefers a two-dimensional structure due to the relativistic effect). Compact-like clusters that are composed exclusively of triangular motifs are preferred for elements without d-electrons (Al) or with (nearly) filled d-band electrons (Ni, Pd, Cu, Ag). Non-compact clusters composed mainly of square motifs connected by some triangular motifs (Rh, Ir, Pt) are favored for elements with unfilled d-band electrons.

An interactive game-based shoulder wheel system for rehabilitation

BACKGROUND

Increases in the aging population and in the number of accidents have resulted in more people suffering from physical impairments or disabilities. Rehabilitation therapy thus attracts greater attention as a means of helping patients recover and return to a normal life. With the extremely long and tedious nature of traditional rehabilitation, patients are reluctant to continue the entire process, thus the expected effects of the therapy cannot be obtained. Games are well known to help patients improve their concentration and shift their attention away from the discomfort of their injuries during rehabilitation. Thus, incorporating game technology into a rehabilitation program may be a promising approach.

METHODS

In this study, a gaming system used for shoulder rehabilitation was developed. The mechanical parts and electric circuits were integrated to mimic the functionalities of a shoulder wheel. Several games were also designed to suit the rehabilitation needs of the patients based on the age and gender differences among the individual users, enabling individuals to undergo the rehabilitation process by playing games. Two surveys were conducted to evaluate the satisfaction of the participants regarding the gaming system.

RESULTS

The results of the online survey among a larger population coincide with the responses of the hands-on participants through a paper-and-pencil survey. Statistical results suggest that the participants are willing to accept this novel approach.

CONCLUSION

This gaming system can distract a patient from the sensation of pain or anxiety, and increase their motivation to participate in the therapeutic program. Advantages in terms of low-cost and easy setup increase the attractiveness of this new equipment for various potential users.

The combined effect of individual and neighborhood socioeconomic status on cancer survival rates

Background

This population-based study investigated the relationship between individual and neighborhood socioeconomic status (SES) and mortality rates for major cancers in Taiwan.

Methods

A population-based follow-up study was conducted with 20,488 cancer patients diagnosed in 2002. Each patient was traced to death or for 5 years. The individual income-related insurance payment amount was used as a proxy measure of individual SES for patients. Neighborhood SES was defined by income, and neighborhoods were grouped as living in advantaged or disadvantaged areas. The Cox proportional hazards model was used to compare the death-free survival rates between the different SES groups after adjusting for possible confounding and risk factors.

Results

After adjusting for patient characteristics (age, gender, Charlson Comorbidity Index Score, urbanization, and area of residence), tumor extent, treatment modalities (operation and adjuvant therapy), and hospital characteristics (ownership and teaching level), colorectal cancer, and head and neck cancer patients under 65 years old with low individual SES in disadvantaged neighborhoods conferred a 1.5 to 2-fold higher risk of mortality, compared with patients with high individual SES in advantaged neighborhoods. A cross-level interaction effect was found in lung cancer and breast cancer. Lung cancer and breast cancer patients less than 65 years old with low SES in advantaged neighborhoods carried the highest risk of mortality. Prostate cancer patients aged 65 and above with low SES in disadvantaged neighborhoods incurred the highest risk of mortality. There was no association between SES and mortality for cervical cancer and pancreatic cancer.

Conclusions

Our findings indicate that cancer patients with low individual SES have the highest risk of mortality even under a universal health-care system. Public health strategies and welfare policies must continue to focus on this vulnerable group.

Multivariate analyses to assess the effects of surgeon and hospital volume on cancer survival rates: a nationwide population-based study in Taiwan

Background

Positive results between caseloads and outcomes have been validated in several procedures and cancer treatments. However, there is limited information available on the combined effects of surgeon and hospital caseloads. We used nationwide population-based data to explore the association between surgeon and hospital caseloads and survival rates for major cancers.

Methodology

A total of 11677 patients with incident cancer diagnosed in 2002 were identified from the Taiwan National Health Insurance Research Database. Survival analysis, the Cox proportional hazards model, and propensity scores were used to assess the relationship between 5-year survival rates and different caseload combinations.

Results

Based on the Cox proportional hazard model, cancer patients treated by low-volume surgeons in low-volume hospitals had poorer survival rates, and hazard ratios ranged from 1.3 in head and neck cancer to 1.8 in lung cancer after adjusting for patients’ demographic variables, co-morbidities, and treatment modality. When analyzed using the propensity scores, the adjusted 5-year survival rates were poorer for patients treated by low-volume surgeons in low-volume hospitals, compared to those treated by high-volume surgeons in high-volume hospitals (P<0.005).

Conclusions

After adjusting for differences in the case mix, cancer patients treated by low-volume surgeons in low-volume hospitals had poorer 5-year survival rates. Payers may implement quality care improvement in low-volume surgeons.

The sub-micron hole array in sapphire produced by inductively-coupled plasma reactive ion etching

The sub-micron hole array in a sapphire substrate was fabricated by using nanosphere lithography (NSL) combined with inductively-coupled-plasma reactive ion etching (ICP-RIE) technique. Polystyrene nanospheres of about 600 nm diameter were self-assembled on c-plane sapphire substrates by the spin-coating method. The diameter of polystyrene nanosphere was modified by using oxygen plasma in ICP-RIE system. The size of nanosphere modified by oxygen plasma was varied from 550 to 450 nm with different etching times from 15 to 35 s. The chromium thin film of 100 nm thick was then deposited on the shrunk nanospheres on the substrate by electron-beam evaporation system. The honeycomb type chromium mask can be obtained on the sapphire substrate after the polystyrene nanospheres were removed. The substrate was further etched in two sets of chlorine/Argon and boron trichloride/Argon mixture gases at constant pressure of 50 mTorr in ICP-RIE processes. The 400 nm hole array in diameter can be successfully produced under suitable boron trichloride/Argon gas flow ratio.

Correlates of anti-EBV EBNA1 IgA positivity among unaffected relatives from nasopharyngeal carcinoma multiplex families

Background:

To determine whether non-viral nasopharyngeal carcinoma (NPC) risk factors might be associated with (and mediated through) Epstein–Barr virus (EBV) serological responses linked to NPC risk, we evaluated predictors of risk of anti-EBNA1 IgA seropositivity and other markers among unaffected relatives from a large NPC family study in Taiwan.

Methods:

Multivariate logistic regression conditioned on family was used to examine the associations between sociodemographic, dietary, lifestyle, and occupational variables and risk of anti-EBV EBNA1 IgA positivity, anti-VCA IgA, and anti-DNase positivity.

Results:

Among 2393 unaffected relatives from 319 multiplex families, 1180 (49.3%) were anti-EBV EBNA1 IgA seropositive. None of the associations with anti-EBNA1 IgA were statistically significant, except for being 31–50 years of age (vs <30, adjusted ORs 0.51–0.57). For one or more EBV serological markers, there were suggestive associations for older age, GuangDong firm salted fish, betel use, current alcohol use, and male gender.

Conclusion:

Overall, we found little evidence to suggest that non-viral NPC risk factors significantly alter EBV serological patterns, suggesting that non-viral NPC risk factors act through pathways independent of EBV serological responses.

A global analysis of molecular markers and phenotypic traits in local chicken breeds in Taiwan

Molecular and phenotypic data have been combined to characterize the genetic diversity of six local chicken breeds maintained with a long-term conservation programme. Hua-Tung, Hsin-Yi, Ju-Chi and Quemoy originated from Taiwan, Shek-Ki is from South China, and Nagoya is from Japan. Molecular tools included 24 microsatellite markers, melanocortin 1 receptor (alpha melanocyte stimulating hormone receptor) (MC1R), the LEI0258 marker located within the major histocompatibility complex (MHC), and mitochondrial DNA. Performance was recorded on the same individuals for body weight, panting rate in summer and antibody response (antigens: Newcastle disease virus and sheep red blood cells). A multivariate method previously proposed for taxonomy was used to combine the different data sets. Melanocortin 1 receptor (alpha melanocyte stimulating hormone receptor) and the MCW330 marker contributed the most to the first axis of the multiple coinertia analysis of molecular markers. Melanocortin 1 receptor (alpha melanocyte stimulating hormone receptor) showed evidence of selection, probably related to its effect on feather colour. The MHC exhibited a large diversity, with 16 alleles of the LEI0258 marker. Immune response traits contributed the most to the principal component analysis of phenotypic data. Eight mitochondrial DNA haplotypes related to clades A, B, C and E were distributed across breeds and revealed an important contribution of Indian and European breeds to Ju-Chi, Quemoy and Hsin-Yi. Phenotypic data contributed less than molecular data to the combined analysis, and two markers, LEI0258 and LEI0228, contributed the most. The combined analysis could clearly discriminate all breeds, except Ju-Chi, which was similar to Quemoy for many criteria, except immune response.

Size effect of Pd clusters on hydrogen adsorption

The size effect of Pd clusters on hydrogen adsorption was investigated by density functional theory calculations. From molecular dynamics simulations, we found that the hydrogen molecules were dissociatively adsorbed on the Pd clusters; the most stable adsorption site was the hollow site. We also found that the adsorption energy increased as the size of Pd clusters decreased. These results were in good agreement with experimental findings. By analyzing the electronic structure, we found that the d-band center shifted toward the Fermi energy as the size of the Pd cluster decreased. This shift resulted in stronger hydrogen bonding.