Much attention is being paid to the planning of public-private partnership (PPP) infrastructure projects. The subsequent implementation phase – when the contract has been signed and the project ‘starts rolling’ – has received less attention. However, sound agreements and good intentions in project planning can easily fail in project implementation. Implementing PPP infrastructure projects is complex, but what does this complexity entail? How are projects managed, and how do public and private partners cooperate in implementation? What are effective management strategies to achieve satisfactory outcomes? This is the fi rst set of questions addressed in this thesis. Importantly, the complexity of PPP infrastructure development imposes requirements on the evaluation methods that can be applied for studying these questions. Evaluation methods that ignore complexity do not create a realistic understanding of PPP implementation processes, with the consequence that evaluations tell us little about what works and what does not, in which contexts, and why. This hampers learning from evaluations. What are the requirements for a complexity-informed evaluation method? And how does qualitative comparative analysis (QCA) meet these requirements? This is the second set of questions addressed in this thesis.
Background: The InsuPad is a medical device to accelerate insulin resorption by applying local heat at the insulin injection site. This crossover study examined the impact of the InsuPad use on postprandial glucose excursions under daily life conditions.
Methods: In 1 study phase, diabetic patients used the InsuPad when injecting bolus insulin before breakfast and dinner and measured their blood glucose 5 times daily (before breakfast, lunch, and dinner and after breakfast and dinner). In the other study phase, blood glucose measurements were maintained without using the InsuPad. The order of the study phases was randomized.
Results: Twenty patients with a high insulin demand took part (30% type 1 diabetes, age 53.7 ± 8.9 years, diabetes duration 14.9 ± 7.4 years; HbA1c 8.3 ± 0.8%; total daily insulin demand 0.97 ± 0.32 IU per kg). Postprandial glucose excursion was reduced by 15.4 mg/dl (95% CI 9.7-21.2 mg/dl; P = .011) after breakfast and dinner if InsuPad was used. The mean blood glucose was lower by 8.8 mg/dl (95% CI 0:3-18:0 mg/dl; P = .099) when using the InsuPad. Safety parameters and the percentage of hypoglycemic (< 60 mg/dl) or hyperglycemic (> 300 mg/dl) blood glucose measurements were not negatively affected by InsuPad use (hypoglycemic values 1.4% vs 1.5%, P = .961; hyperglycemic values 2.6% vs 4.0%, P = .098).
Conclusions: Local heating of the insulin injection site by use of the InsuPad device is an effective and safe method to reduce postprandial blood glucose excursions under daily life conditions without negative side effects on the occurrence of low or high blood glucose values.
Charcot neuro-osteoarthropathy (CN) is a rare complication of diabetic foot syndrome associated with chronic inflammation of the foot and severe, limb-threatening musculoskeletal deformities. Aim of this study was to investigate patients with CN for comorbidities, amputations, ulcers, secondary diseases and mortality.
The study was conducted at a specialized German hospital for patients with diabetes. One-hundred and eleven patients were enrolled, and their course was followed over a period of 15 years. Association of CN with comorbidity, foot ulcers, amputations and mortality was assessed. Clinical course of patients was followed using two standardized questionnaires.
Presence of CN was significantly associated with diabetic retinopathy (p = 0.047), plantar (p < 0.001), tarsal (p = 0.032) and middle-foot ulcers (p = 0.01). A significant correlation between the presence of CN and a history of amputations was seen (p = 0.022). Patients were at increased risk to suffer from subsequent amputations during follow-up when micro- and macrovascular comorbidities such as retinopathy (p = 0.01) and peripheral artery disease (p < 0.001) were present. Additionally, coronary artery disease (CHD) was identified as an independent predictor of mortality in the cohort of this study (OR 6.192, 95 % CI 1.155–33.208, p = 0.033). Median overall survival of patients with CN and CHD was significantly shorter than OS of patients without CHD (7.8 vs. 13.1 years, p = 0.0045, HR 2.8437, 95 % CI 0.9818–8.2364).
In our study, CHD was the most important factor of survival in CN patients. For optimal management of CN, adequate diagnostics and treatment of CHD according to current guidelines should be considered.
Reliability of blood glucose (BG) measurements is a prerequisite for successful diabetes management. Publications on the evaluation of self-monitored glucose values, however, are frequently characterized by a confusion in terminology. We provide an inventory of key terms such as accuracy, trueness, precision, traceability, calibration, and matrix effect to avoid future misunderstanding. Definitions are taken from the metrological literature and international norms and explained in a language intended for nonspecialists in metrology. The terms are presented in light of the need to apply generally accepted definitions. In addition, a description of requirements and components for a sound evaluation of BG measurement systems is presented. These factors will also enable improvement in future comparisons of study results.
Though several questionnaires on self-care and regimen adherence have been introduced, the evaluations do not always report consistent and substantial correlations with measures of glycaemic control. Small ability to explain variance in HbA1c constitutes a significant limitation of an instrument’s use for scientific purposes as well as clinical practice. In order to assess self-care activities which can predict glycaemic control, the Diabetes Self-Management Questionnaire (DSMQ) was designed.
A 16 item questionnaire to assess self-care activities associated with glycaemic control was developed, based on theoretical considerations and a process of empirical improvements. Four subscales, ‘Glucose Management’ (GM), ‘Dietary Control’ (DC), ‘Physical Activity’ (PA), and ‘Health-Care Use’ (HU), as well as a ‘Sum Scale’ (SS) as a global measure of self-care were derived. To evaluate its psychometric quality, 261 patients with type 1 or 2 diabetes were assessed with the DSMQ and an established analogous scale, the Summary of Diabetes Self-Care Activities Measure (SDSCA). The DSMQ’s item and scale characteristics as well as factorial and convergent validity were analysed, and its convergence with HbA1c was compared to the SDSCA.
The items showed appropriate characteristics (mean item-total-correlation: 0.46 ± 0.12; mean correlation with HbA1c: -0.23 ± 0.09). Overall internal consistency (Cronbach’s alpha) was good (0.84), consistencies of the subscales were acceptable (GM: 0.77; DC: 0.77; PA: 0.76; HU: 0.60). Principal component analysis indicated a four factor structure and confirmed the designed scale structure. Confirmatory factor analysis indicated appropriate fit of the four factor model. The DSMQ scales showed significant convergent correlations with their parallel SDSCA scales (GM: 0.57; DC: 0.52; PA: 0.58; HU: n/a; SS: 0.57) and HbA1c (GM: -0.39; DC: -0.30; PA: -0.15; HU: -0.22; SS: -0.40). All correlations with HbA1c were significantly stronger than those obtained with the SDSCA.
This study provides preliminary evidence that the DSMQ is a reliable and valid instrument and enables an efficient assessment of self-care behaviours associated with glycaemic control. The questionnaire should be valuable for scientific analyses as well as clinical use in both type 1 and type 2 diabetes patients.