Spectrum of Endocrine Disorders as Seen in a Tertiary Health Facility in Sagamu, Southwest Nigeria.

BACKGROUND: There is dearth of records on prevalence and spectrum of adult endocrine disorders in Nigeria.
OBJECTIVE: To document the spectrum of endocrine disorders as seen in endocrinology, diabetes, and metabolism (EDM) outpatient clinic, Department of Medicine of Olabisi Onabanjo University Teaching Hospital, Sagamu, Ogun State over a 3-year period.
METHODS: This was a retrospective study of the medical records of all new consultations seen in the EDM outpatient clinic between January 2016 and December 2018. All endocrinology diagnoses were classified according to the 10th revision of the International Statistical Classification of Diseases and Related Health problems (ICD-10). Information on demographic, source of referral, baseline clinical, and biochemical indices were gleaned and subjected to descriptive statistics using SPSS version 21, and results were presented as proportions (frequencies and percentages) and mean (±standard deviation).
RESULTS: Two thousand seven hundred and sixty-five patients were seen and managed at EDM outpatient clinic over the specified time frame. Eight hundred and sixty-three were new cases, age range 16-88, mean of 54.10 (±13.9) years with female preponderance 520 (60.3%) and female-to-male ratio of 1.5:1. The internal referral system constituted the main means of referral to the EDM clinic. The most common endocrine referrals were diabetes mellitus (DM) (697, 80.8%) and thyroid disorders (119, 13.8%) followed by metabolic syndrome (29, 3.36%) and hypothalamic-pituitary disorders (HPOs, 9, 1.04%).
CONCLUSION: The common endocrine cases seen in Sagamu are DM, thyroid diseases, metabolic syndrome, and HPO similar to worldwide trend. Copyright:

INTRODUCTION

To achieve a sustainable healthcare system for our increasing population, health planning remains an undisputed essential aspect of health management. It is imperative therefore to collate health data from time to time to enable proper planning toward achievable healthcare goals.

Endocrine disorders account for >8% of the global disease burden.1 According to the World Health Organization data published in 2017, Nigeria is the 10th country with the highest endocrine-associated mortality worldwide with mortality put at nearly 42,961 (2.11%),2 death rate is 19.56/100,000 deaths, while about 118 people die of endocrine disorders each day, an average of 1 death every 13 min.2 Factors contributing to high endocrine mortality include limited number of endocrinologists, missed or delayed diagnosis by nonspecialists, and priority given to infectious (communicable) diseases.34

In Ghana, the most common primary endocrine disorders are diabetes mellitus (DM), thyroid, and adrenal disorders at frequencies of 79.1%, 13.1%, and 2.2%, respectively.4 In United States, DM and its associated conditions are the most common endocrine disorders encountered followed by thyroid disorders, calcium and metabolic bone disorders, adrenals, reproductive disorders, and hypothalamic–pituitary disorders (HPOs).5

With increasing trend in endocrinopathies in Nigeria, fatality associated with endocrine-related disorders is expected to rise if a strategic action plan is not instituted and implemented. This action plan should focus on workforce training, provision of improved endocrine laboratory assays' services, imaging studies, and genetic testing. Furthermore, provision of health insurance coverage to reduce out-of-pocket payment is advocated. It is therefore imperative to determine and report the spectrum of endocrine diseases regularly for effective health planning purposes in the face of epidemic of noncommunicable diseases. This report would create awareness and aids policymakers, healthcare planners, and the medical community to make informed decision to reduce this trend by aiming to reduce delayed diagnosis and treatment, improve disease outcome, and hopefully reduce the burden on the healthcare system. There is dearth of reports on the spectrum of endocrine disorders seen in adult endocrine specialist clinics in Nigeria. This study aimed to document the prevalence, spectrum, incidence, and referral pattern of endocrine diseases to our tertiary healthcare facility endocrine clinic in Sagamu, Southwestern Nigeria.

METHODS

This was a retrospective study of all new patients referred to the endocrinology, diabetes, and metabolism (EDM) unit of Olabisi Onabanjo University Teaching Hospital (OOUTH) as seen by the consultant endocrinologists and entered into endocrine register. OOUTH is situated in Sagamu, Ogun State, southwest region of Nigeria, and receives referrals from adjoining towns, cities, and states including Lagos. The EDM unit also receives referrals from other units and departments of the hospital. The EDM outpatient clinic runs once a week with an average of 60-80 patients on follow-up visits and 7-12 as newly presenting cases.

This study was carried out in accordance with the principles of the Declaration of Helsinki. Baseline characteristics and measurements including demography, anthropometric indices, source of referral, history, and examination were documented at the first-time visit. Diagnosis based on history, physical examination, and investigations done were collated, documented, and analyzed. Data were reported as proportions (%), range, and mean (±standard deviation [SD]).

RESULTS

Demography

A total number of 2765 patients with endocrine disorders were seen during the period under review. New patients consisted of 863 representing 31.2% of the total number of endocrine cases. Patients were followed up at an average of one to three monthly appointments with a total of 7605 clinic visits. The mean age of studied population was 54.10 (±13.9) years with the mean age of the females significantly lower than their male counterpart (52.9 ± 13.9 vs. 55.9 ± 13.7, P = 0.03), with the age group of 41–60 years being commonly affected. Majority of endocrine cases were seen in females with a female-to-male ratio of 1.5:1. Internal referral system from within the hospital constituted 72.85% of referrals [Table 1] while external referrals were from general hospitals, private hospitals, and outreach/screening programs [Figure 1].

Table 1

Baseline characteristics and referral pattern of the study population (n=863)

Parameters	Total, n (%)
Mean age (years)±SD	54.1±13.9
Age distribution
<20	10 (1.16)
21-30	56 (6.50)
31-40	103 (11.94)
41-50	177 (20.54)
51-60	226 (26.20)
61-70	172 (19.86)
>70	119 (13.80)
Sex distribution
Female	520 (60.3)
Male	343 (39.7)
Source of referral to EDM unit
External	234 (27.15)
Internal	629 (72.85)

EDM – Endocrinology diabetes metabolism; SD – Standard deviation

Figure 1

Pattern of referral to EDM Clinic, Sagamu. O and G – Obstetrics and Gynecology Clinics; CMPC – Community Medicine and Primary Health Care; IHVNL – Institute of Human Virology Nigeria Clinic

Endocrine diseases seen in decreasing order of incidence rate were diabetes in 697 (80.76%) cases, thyroid disorders in 119 (13.78%), metabolic syndrome in 29 (3.36%), HPO in 9 (1.04%) parathyroid and calcium metabolic disorders in 4 (0.48%), gonadal disorders in (0.36%), and adrenal disorder in 1 (0.12%).

Diabetes mellitus

The total number of DM patients were six-hundred and ninety-seven (80.76%): Type 2 DM present in 678 (78.51%) with a female preponderance of 56.5% and Female to Male ratio of 1.3: 1. The mean age (SD) of type 2 DM was 53.9 ± 6.2 years, with the mean age (SD) of females significantly younger than the males (52.1 ± 6.1 vs. 57 ± 6.1) years, [P = 0.02] Type 1 DM seen in 8 (1.15%) of DM cases, with a female preponderance of 75% and female-to-male ratio of 3:1. The mean age (SD) of type 1 DM was 21 ± 5.54 years and no significant differences in the mean age (SD) of females to males (19.50 ± 0.71 vs. 22.67 ± 6.31) years, [P = 0.5].

Secondary DM occurred in 6 (0.86%), predominantly females with a mean age (SD) of 45.8 ± 5.9 years while gestational DM was diagnosed in 5 females (0.72%) with a mean age of 36 ± 3.9 years.

Thyroid gland and hormonal disorders

Thyroid disorders was diagnosed in 119 (13.79%) of patients at the outpatient clinic with females comprising 102 (85.7%) and female to male ratio of 6:1. Their mean age was 36.4 (4.9) years with significant difference in age along gender line, females younger at 34.8 (2.7) than males at 36.9 (3.6) [P = 0.03].

The main cause of thyroid dysfunction was thyrotoxicosis in 81 (68.1%), of which primary hyperthyroidism was 77 (95.1%) as the main reason for presentation, autoimmune Graves' disease in 56 (69.14%) evidenced by clinical features of diffusely enlarged goiter, ophthalmopathy, and/or thyroid acropachy in addition to elevated thyroid autoantibodies such as thyroid peroxidase or anti-thyroglobulin antibody where available. It was the most common cause of primary hyperthyroidism, followed by toxic nodular goiters in 20 (24.69%) and subclinical hyperthyroidism in 1 (1.23%). Other causes of thyrotoxic dysfunction were drug-induced amiodarone in 1 (1.23%), postpartum thyroiditis in 1 (1.23%), and overdose of levothyroxine use in 2 (2.47%).

Hypothyroidism was diagnosed in 11 (9.24%) of thyroid cases, of which autoimmune thyroiditis was the most common cause in 4 (36.4%), followed by postthyroidectomy in 2 (18.2%), subclinical hypothyroidism in 4 (36.4%), and congenital hypothyroidism in 1 (9.0%).

Other types of thyroid disorders were euthyroid goiter in 26 (21.9%) and thyroid cancer in 1 (0.84%).

Parathyroid and calcium metabolic disorders

Parathyroid and calcium metabolic disorders were diagnosed in a total of four patients with a mean age (SD) of 39.5 ± 3.3 years. The disorder included Vitamin-D deficiency, postthyroidectomy hypocalcemia, nutritional hypocalcemia, and primary hypoparathyroidism.

Hypothalamic–pituitary disorders

This was diagnosed in 9 (1.04%) of the patients with mean age (SD) of 39.3 ± 11.5 years and female preponderance 77.8% (7) observed. The most common etiology of the HPOs seen was acromegaly (33.3%). Other causes are listed in Table 2.

Table 2

Classification of endocrine disorders using 10th revision of the international statistical classification of diseases and related health problems

ICD-10 classification	Frequency, n (%)
Pancreas, insulin, and glucagon disorders
Type 1 diabetes	8 (0.93)
Type 2 diabetes	678 (78.51)
Gestational diabetes	5 (0.58)
Secondary DM	6 (0.69)
Thyroid gland and hormonal disorders
Hyperthyroidism	79 (9.15)
Hypothyroidism	11 (1.27)
Thyroiditis	2 (0.23)
Thyroid cancer	1 (0.12)
Others	26 (3.01)
Parathyroid, calcium metabolic bone disorders
Vitamin-D deficiency	1 (0.12)
Post-thyroidectomy hypocalcemia	1 (0.12)
Hypocalcemia (nutritional)	1 (0.12)
Primary hypoparathyroidism	1 (0.12)
Pituitary and hypothalamic disorders
Acromegaly	3 (0.35)
Nonfunctional pituitary adenoma	1 (0.12)
Hypogonadotrophic hypogonadism	1 (0.12)
Prolactinoma	1 (0.12)
Sheehan’ syndrome	1 (0.12)
Craniopharyngioma	1 (0.12)
Transient D I	1 (0.12)
Adrenal disorders
Adrenal adenoma	1 (0.12)
Gonadal disorders
Turner’s syndrome	1 (0.12)
Delayed puberty	1 (0.12)
Gynecomastia	1 (0.12)
Others
Familiar short stature	1 (0.12)
Metabolic syndrome	29 (3.36)
Total	863 (100)

DM – Diabetes mellitus; ICD-10 – 10th revision of the international statistical classification of diseases and related health problems

Adrenal disorder and gonadal disorders

Adrenal disorder and gonadal disorders were reported in 0.12% and 0.36%, respectively [Table 2].

Miscellaneous cases

Other referrals to the clinic included metabolic syndrome and familiar short stature in 30 (34.8%). Twenty-nine patients fulfilled the criteria for metabolic syndrome. Their mean age (SD) was 41.3 ± 6.7 years. The mean age (SD) of males and females were not significantly different (42 ± 7.1 vs. 39.3 ± 5.3 years, P = 0.43). Male gender formed majority 72.4% (21), and male:female ratio was 2.6:1. For this study, patients with DM were excluded.

DISCUSSION

In this 3-year analysis of endocrine consultations at our endocrine clinic, DM, thyroid disorders followed by metabolic syndrome, and HPOs accounted for the highest reasons for endocrine consultations. This is similar to global reports of DM followed by thyroid disorders as the commonest causes of endocrinopathy worldwide.34

From this study, the age group most commonly affected by endocrinopathy was 41–60 years with peak prevalence at 51–60. Endocrine disorders affect the most economically productive groups and translate into reduced productivity with attendant social and financial consequences as well as long-term burden on the family and healthcare system driven by the prevalence of DM.6

Endocrine consultations at our center showed female preponderance. This is a reflection of disease pattern of endocrine disorders which showed predilection for female sex driven mainly by prevalence of DM and autoimmunity of thyroid disorders.7

More than 80% of patients seen in the EDM unit sought treatment for DM and prediabetes condition – metabolic syndrome. Similar to observations in previous studies.45 Metabolic syndrome is defined by IDF8 criteria as impaired fasting glucose (IFG >100 mg/dl but <125 mg/dl) or impaired glucose tolerance (random blood glucose >140 mg/dl <180 mg/dl) plus Triglyceride (TG) >150 mg/dl, High density lipoprotein (HDL-C) <40 mg/dl in males or <50 mg/dl in females, elevated blood pressure (BP) (systolic BP >130 or diastolic >85 mmHg), and obesity BMI >30 kg/m2.

DM remains the most common endocrinopathy in Nigeria, representing 80.8% of referrals to EDM unit. The diabetes prevalence is mainly contributed by type 2 DM (97.3%). This could be attributed to change from our traditional lifestyles to westernization, sedentary lifestyles coupled with inappropriate food intake, increasing obesity, and other risk factors such as increased alcohol intake, significant smoking, and drug use.9 Globally, DM is assuming an epidemic proportion. In 2013, 382 million people had diabetes; it is projected that this number will rise to 592 million by 2035. The greatest rise and burden will be in low- and middle-income countries and Nigeria is not left out.9 Furthermore, the age of presentation of type 2 DM patients at first visit in our clinic are relatively younger compared to developed countries in tandem with Ghana study.4 Urgent interventions are therefore required to curb the surge of DM by the intensifying preventive health education measures and provision of comprehensive diabetes care to ameliorate the burden of DM. Thyroid disorders are the second most common endocrine diseases after DM with prevalence rate of 13.8% and spectrum similar to the previous report from this centre in a 2-year study that documented a rate of 13.64% with hyperthyroidism as the most common cause of presentation among the varied thyroid disorders seen.10 Similar pattern was also documented by a previous study in Lagos.11 The epidemiology of thyroid disorders in our center is a reflection of thyroid autoimmunity – Grave's disease and autoimmune thyroiditis, contrary to earlier studies of increase prevalence of iodine-deficiency disorders due to improved iodine nutrition, reduced by the institution of iodination nutrition program in Nigeria.1213 The predominant histopathological pattern of thyroid disorders reported by Salami et al. in Sagamu was benign follicular goiter.13

HPO is next to thyroid diseases among the core endocrinopathies seen. Acromegaly is the most common at 0.35% of the total cases and the most common cause of HPO. Endocrine Society Clinical Practice guidelines suggest screening for acromegaly with measurement of serum insulin growth factor-1.14 Sheehan's syndrome caused by hemorrhagic infarction of pituitary gland following severe hypotension from blood loss and poor obstetric care was found in 0.12% of cases.15 It is characterized by pituitary hormones deficiency, amenorrhea, and high risk of cardiovascular disease if not treated. Craniopharyngioma is a squamous cell tumor arising from Rathke's pouch remnants and is uncommon in adults (0.12%).16 Modality of its management is by surgery and/or irradiation. Lifelong hormone replacement therapy is essential for improved quality of life and survival in hypopituitarism. Other pituitary diseases seen are nonfunctional pituitary macroadenoma, functional pituitary microadenoma (prolactinoma), and transient cranial diabetes insipidus with temporary disturbance in water and salt balance triggered by head trauma.

Parathyroid, Calcium and Metabolic bone disorders are related to hypoparathyroidism post-thyroidectomy as are Vitamin D deficiency, nutritional hypocalcaemia and primary hypoparathyroidism in this study. However, this may not be a true reflection of the prevalence Calcium and Metabolic bone disease that usually coexist. This is due to non-availability and affordability of bioassays for parathyroid and bone markers, as well as Dual-energy X-ray absorptiometry (DXA) studies for their diagnosis.

Referrals to our EDM unit were mostly from within the hospital. The factors contributing to low external referrals pattern observed may be due to missed or late diagnosis attributable to limited knowledge in core endocrine-related conditions by nonspecialists and priority given to the management of infectious (communicable) over noncommunicable. This negatively impacts referral to endocrinologists. The endocrinologists are faced with the challenge of limited accessibility to investigative services, especially in public hospital setting. Therefore, there is a urgent need to develop our level of endocrine practice in Nigeria by upgrading and expanding our endocrine investigative services, including imaging and genetic testing facilities.

CONCLUSION

The frequency of new endocrine cases in our center is 31.2% with spectrum that is similar to other reports. Early screening and referral are advocated to reduce the morbidity and mortality and improve quality of life associated with endocrine disorders.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.