Progresión de las principales complicaciones microvasculares diabéticas en un periodo >1 año desde su diagnóstico en pacientes del norte del Perú

Progression of major diabetic microvascular complications over a period >1 year since their diagnosis in patients from northern Peru

Introducción. Las complicaciones microvasculares son la principal consecuencia de la progresión de la diabetes mellitus (DM). Estas complicaciones afectan significativamente la calidad de vida y aumentan la tasa de mortalidad en estos pacientes. La neuropatía, la retinopatía y la nefropatía diabéticas son las complicaciones microvasculares más frecuentes.

Objetivo. Describir la progresión de las principales complicaciones microvasculares diabéticas en un periodo >1 año desde su diagnóstico en pacientes atendidos en un hospital regional del norte del Perú.

Materiales y métodos. Estudio descriptivo retrospectivo y longitudinal, realizado con datos de 185 pacientes diagnosticados con al menos una de las principales complicaciones microvasculares diabéticas (i.e., nefropatía, neuropatía y retinopatía diabéticas) atendidos durante 2023 en el Hospital Regional de Cajamarca, Perú. Se recolectó información sobre la etapa o fase clínica de cada complicación en 5 diferentes momentos (momento de diagnóstico y a los 3, 6, 12 meses y en la última evaluación desde el diagnóstico). Para evaluar la progresión de la nefropatía, la neuropatía y la retinopatía diabéticas, las medidas de estas complicaciones microvasculares (i.e., frecuencia o proporción de pacientes en las diferentes etapas o fases de la condición) fueron comparadas en los múltiples momentos evaluados mediante las pruebas Friedman y Q de Cochran.

Resultados. La mayoría de los pacientes fueron mujeres (61.62%), con una mediana de edad de 60 años (RIQ: 50.50-69) (adultos mayores: 50.81%); la edad promedio de diagnóstico fue 52.24±12.61 años y la mediana del tiempo transcurrido desde el diagnóstico de DM fue 6 años [RIQ: 2-9]. La neuropatía diabética fue la complicación más frecuente (58.92%), seguida de la retinopatía diabética (40.00%). La progresión de la nefropatía diabética entre el momento de diagnóstico (etapa 1: 81.36%; etapa 2: 8.47%; etapa 3: 8.47%) y la última valoración (23.81%, 49.21%, 22.22%) fue estadísticamente significativa (p<0.001). Este también fue el caso para la nefropatía diabética (79.82% en fase subclínica y 20.18% en fase clínica al momento del diagnóstico vs. 38.46% y 51.28% en la última valoración [>1 año desde el diagnóstico], p<0.001).

Conclusión. Se observó un empeoramiento estadísticamente significativo de la neuropatía diabética y de la nefropatía diabética entre el momento de diagnóstico y la última evaluación (>1 año desde el diagnóstico). La prevalencia de cada una de las tres complicaciones microvasculares fue alta, en particular la neuropatía diabética.

Introduction: Microvascular complications are the main consequence of the diabetes mellitus (DM) progression. These complications significantly affect quality of life and increase the mortality rate of these patients. Diabetic neuropathy, retinopathy, and nephropathy are the most frequent microvascular complications.

Objective: To describe the progression of the major diabetic microvascular complications over a period >1 year since their diagnosis in patients treated at a regional hospital in northern Peru.

Materials and methods: This retrospective, longitudinal, descriptive study was conducted using data from 185 patients diagnosed with at least one of the major diabetic microvascular complications (i.e., diabetic nephropathy, neuropathy, and retinopathy) treated during 2023 at the Regional Hospital of Cajamarca, Peru. Information regarding the clinical stage or phase of each complication was collected at 5 different time points: at diagnosis, at 3, 6, and 12 months, and at the last evaluation since diagnosis. To assess the progression of diabetic nephropathy, neuropathy, and retinopathy, the measures of these microvascular complications (i.e., frequency or proportion of patients in the different stages or phases of the condition) were compared across the multiple time points using Friedman and Cochran’s Q tests.

Results: Most patients were women (61.62%), with a median age of 60 years (IQR: 50.50–69) (older adults: 50.81%). The mean age at diagnosis was 52.24 ± 12.61 years, and the median time elapsed since DM diagnosis was 6 years [IQR: 2–9]. Diabetic neuropathy was the most common complication (58.92%), followed by diabetic retinopathy (40.00%). The progression of diabetic nephropathy between the time of its diagnosis (stage 1: 81.36; stage 2: 8.47%; stage 3: 8.47%) and the last evaluation (23.81%, 49.21%, 22.22%) was statistically significant (p<0.001). This was also the case for diabetic nephropathy (79.82% in the subclinical phase and 20.18% in the clinical phase at the time of diagnosis vs. 38.46% and 51.28% at the last assessment [>1 year since diagnosis], p<0.001).

Conclusion: A statistically significant worsening of diabetic neuropathy and diabetic nephropathy was observed between the time of complication diagnosis and the last evaluation (>1 year since diagnosis). The prevalence of each of the three microvascular complications was high, particularly diabetic neuropathy.

Original research

Michiko Melissa Perez-Cunavi1 José Alexander Pisco Sánchez1 José Ander Asenjo-Alarcón1

1 Universidad Nacional Autónoma de Chota - Faculty of Health Sciences - Chota, Cajamarca - Peru.

Open access

Received: 11/07/2025

Accepted: 07/05/2026

Corresponding author: José Ander Asenjo-Alarcón. Facultad de Ciencias de la Salud, Universidad Nacional Autónoma de Chota. Chota, Cajamarca. Perú. E-mail: ander1213@hotmail.com.

Keywords: Monitoring, Ambulatory; Diabetes Complications; Diabetes Mellitus, Type 2; Patients; Hospitals, Public; Peru (MeSH).

Palabras clave: Monitoreo Ambulatorio; Complicaciones de la Diabetes; Diabetes Mellitus Tipo 2; Pacientes; Hospitales Públicos; Perú (DeCS).

How to cite: Perez-Cunavi MM, Pisco-Sánchez JA, Asenjo-Alarcón JA. Progression of major diabetic microvascular complications over a period >1 year since their diagnosis in patients from northern Peru. Rev. Fac. Med. 2026;74:e121536. English. doi: https://doi.org/10.15446/revfacmed.v74.121536.

Cómo citar: Perez-Cunavi MM, Pisco-Sánchez JA, Asenjo-Alarcón JA. [Progresión de las principales complicaciones microvasculares diabéticas en un periodo >1 año desde el diagnóstico de diabetes en pacientes del norte del Perú]. Rev. Fac. Med. 2026;74:e121536. English. doi: https://doi.org/10.15446/revfacmed.v74.121536.

Copyright: ©2026 The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, as long as the original author and source are credited.

Abstract

Resumen

Introduction

Diabetes mellitus (DM) is a severe chronic disease characterized by elevated blood glucose levels.1,2 According to the World Health Organization, there were 830 million people with this disease worldwide in 2022, showing a considerable increase since 1990 (200 million), and its prevalence has been increasing more rapidly in low- and middle-income countries.3

DM is classified into several categories, including gestational diabetes, type 1 diabetes (T1D), and type 2 diabetes (T2D), with the latter being the most common (>95% of cases).1-3 Given its chronic nature, patients with DM develop several complications, which can be classified into microvascular and macrovascular.2,4,5 Microvascular complications are the main consequence of DM progression, typically occurring within 5–20 years after disease onset.4 These complications significantly affect quality of life, exerting long-term negative effects on vital organs such as the eyes, kidneys, heart, and brain, and increasing the mortality rate.4-6 The main microvascular complications are diabetic neuropathy, retinopathy, and nephropathy.4,6

Diabetic neuropathy is a clinical syndrome characterized by pain due to lesions in the somatosensory system.5 Estimates are that approximately 50% of patients with diabetes develop some type of neuropathy, although reported diabetic neuropathy prevalence varies significantly among studies (6-60%).7 Depending on the affected nerves, it can be classified into peripheral, autonomic, proximal, and focal. The first is the most frequent form,5,7,8 with a prevalence between 7% and 75% in adults with DM;9 in fact, diabetic peripheral neuropathy (DPN) reportedly accounts for up to one third of peripheral neuropathy cases.8 DPN is characterized by bilateral pain, numbness, and paresthesia in the extremities, and severe cases can cause foot ulcers that may lead to amputation.8,10

Diabetic retinopathy is one of the most frequent microvascular complications of diabetes and the leading cause of vision loss in working-age adults.11,12 This complication results from chronic hyperglycemia, which causes damage to retinal blood vessels, disrupting the blood-retinal barrier and leading to anomalous neovascularization and subsequent alteration of retinal structure.11 Literature shows that the global prevalence of this complication is 22.3%, and in Latin America and the Caribbean it reaches 37.3% and 40.6% in patients with T2D and T1D, respectively.13

Diabetic retinopathy is divided into two stages: early (non-proliferative diabetic retinopathy) and advanced (proliferative diabetic retinopathy).5 In Asian populations, the annual progression probability from no retinopathy to mild retinopathy is 6.1%, from mild to moderate is 7.0%, and from moderate to severe/proliferative is 19.3%.14

Diabetic nephropathy is a frequent and severe complication of diabetes that causes progressive renal function decline, eventually leading to chronic kidney disease, and is the leading cause of dialysis requirement in these patients in many countries.5,15 It is characterized by chronic albuminuria, decreased glomerular filtration rate, and increased blood pressure.15 Approximately 20% to 40% of patients with diabetes develop nephropathy,5,16 but prevalence data vary widely among countries due to factors related to ethnicity and economic development, with values ranging from 2.9% in Ethiopia6 and 10.8% in Saudi Arabia5 to 31.1% in Mexico15 and 31.2% in Canada.15

Progression of diabetic microvascular complications largely depends on the control of diabetes itself, but concomitant risk factors can accelerate transition through the different phases of the complications. For example, the development and progression of diabetic neuropathy are influenced by factors such as diabetes duration, glycemic control, age, obesity, dyslipidemia, insulin resistance, chronic low-grade inflammation, lifestyle, cardiovascular health, and genetic predisposition.7 As neuropathy advances, a greater number of neural branches are affected, which worsens and exacerbates clinical manifestations in these patients, including decreased gait velocity, prolonged gait cycle, increased stride length, and reduced pelvic obliquity and rotational range of motion.17

Concerning diabetic retinopathy, the most critical risk factors for development and progression are DM duration and poor glycemic control, with other factors including hypertension and renal function status.18 In the initial stage of this complication, the retina develops resilience to high blood sugar, remaining healthy for a period. When this resilience is lost, the retina begins to progressively deteriorate.19

Finally, several related modifiable risk factors (hypertension, glycemic control, dyslipidemia, and smoking) and non-modifiable risk factors (race, age, gestational status, genetic profile, and sex) have been reported for diabetic nephropathy.20 Recent studies on its pathogenesis indicate a progression of inflammation and fibrosis from the tubules to the glomeruli in the initial stages. Periodic measurement of serum biochemical indicators such as the interleukin-6:omentin-1 ratio could facilitate the detection of diabetic nephropathy in its early stages before microalbuminuria is identified.21

Therefore, this study aimed to describe the progression of the main diabetic microvascular complications over a period >1 year since their diagnosis in patients treated at a regional hospital in northern Peru.

Materials and methods

Study design

Retrospective, longitudinal, descriptive study.

Study population and sample

The study population consisted of individuals with T2D treated in 2023 at the outpatient or inpatient departments of the nephrology, neurology, or endocrinology services of the Hospital Regional de Cajamarca, a tertiary care institution in northern Peru (N=717). Based on this study population, the adjusted sample size was calculated using a 95% confidence level, an expected proportion of 50%, and a 5% margin of error, resulting in a sample of 185 patients. These patients were selected via simple random sampling after verifying the following inclusion and exclusion criteria in their medical records:

Inclusion criteria

• Patients with at least one of the following diabetic microvascular complications documented in their medical records: nephropathy, neuropathy, or retinopathy.
• Patients with documented, continued diabetes management since their microvascular complication diagnosis (with a minimum of 3-, 6-, and 12-month follow-up data).

Exclusion criteria

• Patients not evaluated in any of the aforementioned hospital services for a period >1 year at the time of data collection.
• Patients with incomplete medical records regarding the variables of interest.

Data collection and variables

Once selected, the following data were extracted for each patient after a detailed medical record review: biological sex, age (30–59 years and ≥60 years), marital status (married, single, common-law marriage, widowed), age at diagnosis (30–59 years and ≥60 years), time since DM diagnosis (0–5 years, 6–9 years, and ≥10 years), presence of diabetic nephropathy, neuropathy, or retinopathy, and time since the development of these microvascular complications.

Information was also collected on the clinical stage or phase of the complication at diagnosis, 3 months, 6 months, 12 months, and at the last evaluation since diagnosis. This included nephropathy stages 1–5 (ranging from normal or increased glomerular filtration rate to kidney failure); neuropathy phases (subclinical [asymptomatic], diffuse clinical [pain, paresthesia, sensory loss, and internal symptom involvement], and focal syndromes [cranial or specific nerve involvement]); and retinopathy (proliferative phase [neovascularization to retinal detachment] and non-proliferative phase [microaneurysms; categorized as mild, moderate, or severe]). Data were collected between April and May 2024, and then recorded and organized using a format based on the Technical Health Standard for Epidemiological Surveillance of Diabetes of the Peruvian Ministry of Health NTS N° 210-MINSA/CDC-2024.22

Statistical analysis

Categorical variables were described using absolute frequencies and percentages with their respective 95% confidence intervals (95% CI). Numerical variables were expressed as means, medians, standard deviations, interquartile ranges (IQR), and minimum and maximum values, depending on the presence or absence of a normal distribution evaluated via the Lilliefors-corrected Kolmogorov-Smirnov test. Numerical variables were also categorized to provide a more comprehensive presentation of the results.

To evaluate the progression of diabetic nephropathy, neuropathy, and retinopathy, these microvascular complication measures (i.e., frequency or proportion of patients at different stages or phases of the condition) were compared across multiple evaluation points (complication diagnosis, at 3, 6, and 12 months since its diagnosis, and last follow-up) using Friedman and Cochran’s Q tests. Statistical significance was set at p<0.05 and all analyses were performed using Jamovi (version 2.3.28).

Ethical considerations

The study followed the ethical principles for human research established in the Declaration of Helsinki23 and was approved by the Research and Ethics Committee of the Hospital Regional de Cajamarca, as per Letter No. 119-2024-GR.CAJ/DRS/HRDC/CDEI dated May 10, 2024, and by an ad hoc scientific committee of the Faculty of Health Sciences of the Universidad Nacional Autónoma de Chota, as recorded in Faculty Resolution No. 044-2024-FCCSS-UNACH/C dated March 11, 2024.

Results

The median age of the patients was 60 years (IQR: 50.50–69 years; range: 31–89 years), with 50.81% aged 60 years or older, 61.62% being female, and 67.03% being married. The mean age at DM diagnosis was 52.24±12.61 years (maximum - minimum: 21–81 years), and the median time since DM diagnosis was 6 years (IQR: 2–9 years; maximum - minimum: 1–48 years), with the 0–5 years range being the most frequent (49.73%). The main characteristics of the sample are presented in Table 1.

Table 1. Sociodemographic and diabetes diagnosis-related characteristics of the sample (n=185).

Variables		n (%)	95%CI
Sex
	Female	114 (61.62)	54.6-68.6
	Male	71 (38.38)	31.4-45.4
Age
	Adult (30-59 years)	91 (49.19)	42.0-56.4
	Older adult (≥60 years)	94 (50.81)	43.6-58.0
Marital status
	Married	124 (67.03)	60.2-73.8
	Single	39 (21.08)	15.2-27.0
	Cohabitation	14 (7.57)	3.8-11.4
	Widowed	8 (4.32)	1.4-7.2
Age at diagnosis
	Adult (30-59 years)	126 (68.11)	61.4-74.8
	Older adult (≥60 years)	59 (31.89)	25.2-38.6
Time since diagnosis
	0-5 years	92 (49.73)	42.5-56.9
	6-9 years	51 (27.57)	21.2-34.0
	≥10 years	42 (22.70)	16.7-28.7

Source: Own elaboration.

The presence of diabetic nephropathy, neuropathy, and retinopathy was reported in 31.90%, 58.92%, and 40.00% of the patients, respectively (Table 2), while the mean time since the onset of these microvascular complications was 2.81±2.17 years (maximum - minimum: 1–9 years), 3.65±2.69 years (maximum - minimum: 1–14 years), and 3.85±2.91 years (maximum - minimum: 1–15 years), respectively.

Table 2. Presence of diabetic nephropathy, neuropathy, and retinopathy in the sample (n=185).

Microvascular complications		n (%)	95%CI
Diabetic nephropathy
	Yes	59 (31.90)	25.2-38.6
	No	126 (68.10)	61.4-74.8
Diabetic neuropathy
	Yes	109 (58.92)	51.8-66.0
	No	76 (41.08)	34.0-48.2
Diabetic retinopathy
	Yes	74 (40.00)	32.9-47.1
	No	111 (60.00)	52.9-67.1

Source: Own elaboration.

Regarding the progression of diabetic nephropathy between its diagnosis and the last evaluation (>1 year since its diagnosis), the proportion of stage 1 patients decreased from 81.36% to 23.81% during this period. In contrast, stages 2 and 3 showed an increase (from 8.47% to 49.21% and from 8.47% to 22.22%, respectively), and this difference was statistically significant (Friedman test: p<0.001) (Figure 1).

Figure 1. Distribution of patients with diabetic nephropathy by disease stage at multiple evaluation time points (n=59).

Source: Own elaboration.

Concerning the progression of diabetic neuropathy during the study period, the frequency of patients in the subclinical phase decreased from 79.82% to 38.46% between its diagnosis and the last evaluation (>1 year since its diagnosis), while the proportion of patients in the clinical phase increased from 20.18% to 51.28%. In the case of focal syndromes, their occurrence was reported starting 6 months after its diagnosis, increasing from 2.75% at that point to 10.26% at the last evaluation. This difference was statistically significant (Friedman test: p<0.001), as shown in Figure 2.

Figure 2. Distribution of patients with diabetic neuropathy by disease phase at multiple evaluation time points (n=109).

Source: Own elaboration.

Finally, changes in diabetic retinopathy progression between DM diagnosis and the last evaluation (>1 year since its diagnosis) were minimal. The proportion of patients in the non-proliferative phase decreased from 97.30% to 95.12%, while in the proliferative phase it increased from 2.70% to 4.88%, showing no significant differences (Cochran Q test: p=0.539) (Figure 3).

Figure 3. Distribution of patients with diabetic retinopathy by disease phase at multiple evaluation time points (n=74).

Source: Own elaboration.

Discussion

This study found that diabetic neuropathy was the most frequent (58.92%) among the three evaluated microvascular complications, followed by diabetic retinopathy (40.00%). These findings align with the relevant literature, as diabetic neuropathy is reported to be one of the most common chronic complications of DM7,8 as well as the most frequent microvascular complication.5 Regarding its prevalence, international studies indicate that it increases with age and diabetes duration, ranging from 6% to 15% in patients newly diagnosed with T2D to over 50% in patients with a disease duration of more than 10 years.5,7,8

Considering that the median time since DM diagnosis in our study was 6 years and that time since diagnosis did not exceed 5 years in 49.73% of patients, the observed prevalence of diabetic neuropathy is remarkably higher than that described in most literature (≥50%).5,8 For instance, in a study including 2 048 diabetic patients from 13 centers in Beijing (China), Pan et al.24 reported that the prevalence of DPN, the most common form of diabetic neuropathy, was 35.34% in patients with T2D. Meanwhile, in Finland, Partanem et al.25 found that among 133 patients with newly diagnosed non-insulin-dependent DM, 8.3% had diabetic neuropathy at diagnosis, which increased to 41.9% after 10 years. Nevertheless, a recent literature review indicates that the prevalence of this microvascular complication varies widely across studies, ranging from 6% to over 60%.7 Similarly, recent studies state that the estimated prevalence of DPN ranges from 7% to 75% in adults with DM, and this figure continues to rise.9

As for diabetic retinopathy, the prevalence observed in this study (40.0%) is partially similar to that reported for Latin America and the Caribbean in the systematic review and meta-analysis by Medina et al.13 in 2024 (44 studies; 48 021 patients with diabetes). They found a pooled prevalence of 40.6% in patients with T1D (95%CI: 34.7-46.6%; I2: 92.1%; 9 studies, 4 505 patients with T1D) and 37.3% in those with T2D (95%CI: 31.0-43.8%; I2: 97.7%; 19 studies, 11 569 patients with T2D).

However, this figure exceeds the pooled prevalence described for Spain in the meta-analysis by Romero-Aroca et al.:26 19.93% for the 2001–2020 period (95%CI: 14.09-27.14%, minimum: 8.56%, maximum: 35.70%; I2: 99%, 10 studies), 28.85% for the 2001–2008 period (95%CI: 23.14-31.71%, minimum: 26.11%, maximum: 35.7%; I2: 97%, 4 studies), and 15.28% for the 2009–2020 period (15.28%; 95%CI: 10.50-22.35%, minimum: 8.56%, maximum: 17.9%). It is also higher than the global pooled prevalence for 2020 (22.27%, 95%CI: 19.73-25.03%; 59 studies),27 the 1980-2008 period (34.6%, 95%CI: 34.5-34.8%; 35 studies),5 and the prevalence reported for the United States (28.5%).5 Finally, it is remarkably higher than the pooled prevalence of 20.53% (95%CI: 20.21-20.85%; I2: 97.99%, 20 studies) reported for Gulf Cooperation Council countries in the systematic review and meta-analysis by Mohamed et al.,11 where patients from Saudi Arabia were the most affected (69.75%; 95%CI: 64.98-74.21%) and those from the United Arab Emirates were the least affected (6.0%; 95%CI: 2.78-11.08%).

This heterogeneity across studies could be driven not only by demographic and ethnic differences, but also by major socioeconomic disparities that condition the capacity of national healthcare systems to provide adequate care for these patients.

In this study, 31.90% of patients had diabetic nephropathy. This prevalence is higher than that described in patients with T2D in North America (28.2%; 95%CI: 19.7-36.7%; I2: 100%; p=0.00; 11 studies),15 the United States of America (24.2%; 95%CI: 13.8-34.5%; I2: 100%; p=0.00; 5 studies),15 China (21.8%, 95%CI: 18.5-25.4%),5 southern India (26.1%),5 Saudi Arabia (10.8%),5 and Ethiopia (2.9%, IC95%: 1.2-4.7%),6 but similar to the prevalence found in studies from Mexico (31.1%, 95%CI: 20.8-41.5%; I2: 83%; p<0.01; 3 studies)15 and Canada (31.2%, 95%CI: 25.8-36.5%; I2: 98%; p<0.01; 3 studies).15 Consequently, depending on factors such as ethnicity and national economic development levels, between 20% and 40% of individuals with diabetes develop this microvascular complication.5,16

In our patient population, beyond ethnic, geographical, and demographic factors, the high frequency of this microvascular complication could be linked to economic factors inherent to national development. Said factors may limit the proper management of diabetes and its complications at both the individual and healthcare system levels, particularly among low-income populations, which World Bank data indicates accounted for 33.8% of the Peruvian population in 2023.28

The analyzed microvascular complications showed distinct progression patterns in this study. Concerning nephropathy, the proportion of stage 1 patients decreased considerably (81.36% vs. 23.81%) between its diagnosis and the last evaluation (>1 year post-diagnosis), whereas the proportion of patients in stages 2 and 3 increased, with statistically significant differences across all cases. A similar trend was observed with diabetic neuropathy, which showed a statistically significant decrease and increase in the proportions of subclinical and clinical phase patients, respectively, particularly from 6 months post-diagnosis onward. Likewise, focal syndromes became more frequent starting 6 months post-diagnosis, yielding a significantly higher proportion of patients at the final evaluation than at the time of disease diagnosis. Conversely, progression in diabetic retinopathy severity was minimal between its diagnosis and the final evaluation (>1 year post-diagnosis).

A review of the relevant literature revealed no studies reporting long-term measurements of these complications over a period similar to that analyzed herein (i.e., from complication diagnosis to more than 1 year post-diagnosis), which limits the comparison of these results. However, regarding diabetic nephropathy and neuropathy, a clear trend toward worsening over time was observed. Although the progression rate of each complication varies depending on intrinsic and extrinsic factors that are mostly modifiable,5,7,8,13,15,26 this marked worsening trend demonstrates that patient management must incorporate strategies targeting these factors to minimize progression risk as much as possible. These strategies should ideally be implemented at initial DM diagnosis and, whenever possible, before the onset of one or multiple microvascular complications.

Diabetic neuropathy presents in various ways and frequently goes unnoticed for years after DM onset, making its diagnosis and management highly challenging.29,30 This high probability of delayed diagnosis contributes to a heavy morbidity burden, including painful diabetic neuropathy, foot ulcers, amputations, and increased mortality.30

Since their combination can induce direct axonal damage and nerve ischemia, the endothelial dysfunction, oxidative stress, and chronic inflammation characteristic of diabetic neuropathy lead to polyneuropathy, a condition characterized by neuropathic pain.31 Nerve fiber damage in diabetic neuropathy causes sensory disturbances responsible for numbness, tingling, and sensation loss, which are clinical manifestations of distal polyneuropathies such as diabetic foot.32 Consequently, DPN alters body and movement biomechanics, increases mechanical stress during gait, and predisposes individuals to injuries from the repetitive effects of these strains.17 Consequently, contextualized, family-oriented educational interventions on limb self-care improve self-care practices and potentially reduce the risk of related complications.33

As mentioned above, progression of diabetic retinopathy severity between its diagnosis and the final evaluation (>1 year post-diagnosis) was minimal, with the proportion of patients in the proliferative phase increasing by just over 2% (2.70% vs. 4.88%). The literature indicates that the progression of this microvascular complication toward the proliferative phase is influenced by multiple factors, including cholesterol and triglyceride levels, estimated glomerular filtration rate, ethnicity, retinopathy characteristics, sex, diabetes duration, and blood pressure.34

Physiologically, non-proliferative diabetic retinopathy is characterized by increased retinal venous oxygen saturation alongside decreased retinal blood flow and oxygen metabolism.35 Despite compensatory mechanisms to counteract these changes, the disease progresses to proliferative diabetic retinopathy in some patients, a phase associated with ocular complications that can lead to irreversible retinal damage and significant vision loss.35 Although the percentage of patients progressing to the proliferative phase was minimal during our study period, the potential visual consequences of such progression underscore the need for implementing timely strategies to delay advancement, minimizing the impact on the patient’s clinical status and quality of life.

Similar to neuropathy, diabetic nephropathy showed a marked progression, considering that between its diagnosis and the final evaluation (>1 year post-diagnosis), the proportion of stage 1 patients decreased from 81.36% to 23.81%, while stage 2 and 3 patients increased from 8.47% to 49.21% and 8.47% to 22.22%, with these differences being statistically significant. This microvascular complication is characterized by increased albumin excretion and a decreased glomerular filtration rate. The onset and progression of these manifestations are linked to factors such as advanced age, longer diabetes duration, inadequate glycemic control, and hypertension.36 As diabetic nephropathy progresses, metabolic insufficiency, oxidative stress, endoplasmic reticulum stress, and inflammation can lead to irreversible podocyte destruction, aberrant apoptosis, and autophagy.37 Since there is no definitive cure for this complication, rigorous management through strict glucose and blood pressure control remains essential.37

Given the statistically significant worsening of diabetic neuropathy and nephropathy observed between their diagnosis and the final evaluation (>1 year post-diagnosis), primary care services in northern Peru and nationwide should develop and implement targeted strategies. They should focus on improving patient knowledge regarding diabetes and its potential complications to promote better self-care, while ensuring continuous monitoring for early detection, ultimately enabling adequate management and ensuring a better quality of life.38-41

This study has some limitations that must be considered when interpreting the results. First, its retrospective nature and the data source used (medical records) may introduce information and measurement biases, as the quality of the data recorded by treating healthcare professionals cannot be fully verified. However, it should be noted that specific information regarding the characteristics and progression of microvascular diabetes complications in these patients is exclusively available within this data source. Furthermore, patient assessment by specialists for the presence of diabetic neuropathy, nephropathy, and/or retinopathy minimizes measurement bias. Second, the established inclusion and exclusion criteria introduce a risk of selection bias. By restricting inclusion to patients with complete medical records, rigorous follow-up, and full data at 3, 6, 12, and >12 months, the sample may overrepresent highly adherent or clinically stable individuals (survival/attrition bias). This design inadvertently excludes patients who defaulted from follow-up or management—due to long traveling distances, lack of financial resources for appointments, or non-adherence—as well as those who died within the first year following DM diagnosis.

Conclusion

This study observed a statistically significant worsening of diabetic neuropathy and nephropathy between their diagnosis and the final evaluation (>1 year post-diagnosis) in patients from northern Peru, highlighting the need for more exhaustive monitoring to prevent or manage the progression of these complications. For retinopathy, changes were minimal, with a very slight increase in the proportion of patients in the proliferative phase. Finally, the prevalence of each of the three microvascular complications was high, particularly diabetic neuropathy (nearly 60%).

Conflicts of interest

None stated by the authors.

Funding

None stated by the authors.

Acknowledgments

None stated by the authors.

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