case study 10 -- elderly on insulin therapy

Elizabeth Ho Moon Liang

*** CASE STUDY 10 Elderly Poorly Controlled Diabetes on Insulin

Dated: 18 September 2007 (Final edition 21 January 2008)

Patient’s Name: Kwok C.L. NIRC: S05*****F

*** Submitted to SNB forAPN Certification

TABLEOFCONTENTSPage

1. Patient Profile 2

2. Health Assessment 2

3. Physical Examination 3

4. Diagnosis 4

5. Management 5

6. Evaluation 9

7 APN Reflection and Learning Points 9

MrKenneth Kwok, a 68-yearold gentleman, has diabetes and hyperlipidemia for7 years.Recently in November2006, he was diagnosed with early diabetic nephropathy and

hypertension. He started on insulin therapy in addition to his oral antihyperglycemic agents on12 August 2006. This case study will be based on the visit 07 April 2007 focusing on themanagement of diabetes mellitus in an elderly patient on insulin injections.


PATIENT PROFILE

Mr Kenneth Kwok (S05*****F) is a 68-year old gentleman who has diabetes and

hyperlipidemia for 7 years. He started on insulin therapy in addition to his oral hypoglycemic

agents on 12 August 2006. In November 2006, he was diagnosed with early diabetic nephropathy

after 2 episodes of increased albumin : creatinine ratios of 30 to 300mg/g. There are no other

diabetic microvascular and macrovascular complications. During his last visit to the polyclinic

on 14 November 2006, he was noted to have elevated blood pressure reading of 142/ 90mmHg

for the second episode. This case study will focus on the management of diabetes mellitus in an

elderly patient on insulin injections.

HEALTHHISTORY

Chief Complaint: I saw Mr Kwok and his wife on 07 April 2007 for his usual medical review.

Mr Kwok felt well and had no complaints. Mr Kwok’s injections were given by Mrs Kwok and

his wife cited the night insulin dosage correctly. In particular, there were no hypoglycemic

episodes. His fasting home glucose monitoring ranged from 5.5 to 5.7mmol/L. His HbA1C%

was 7.9% with a fasting blood glucose of 7.5mmol/L. His Lovastatin dose of 20mg at night had

been changed to Simvastatin 15mg the previous visit due to the sub-optimal control of low-

density lipoprotein at the level of 3.00mmol/L. He claimed to be compliant and tolerant to the

change of statins from Lovastain 20mg to Simvastatin 15mg every night. He experienced no

muscle pain, tenderness or weakness from the medication.

SOCIALHISTORY

Mr Kwok is a retiree currently living with his wife. His children are married and staying with

their own family units. This elderly couple has to cope with managing their chronic diseases.

Mrs Kwok also has diabetes mellitus but she is only on oral hyperglycemic agents. Her glycemic

control is better than Mr Kwok. Mrs Kwok draws the insulin dosage and administers the insulin

injection every night for Mr Kwok at 10pm. Both of them usually eat at home where the food is

prepared by Mrs Kwok. Recently, Mr Kwok had been drinking Pokka green tea, 100 Plus and

Yakult about 3 times a week due to the hot weather and constipation. Mr and Mrs Kwok walk

around the block after dinner time about 3 times a week, 20 minutes each time. However, they

cannot walk further due to the pain in Mr Kwok’s osteoarthritic knees.


DRUGALLERGY: None known.

CURRENTMEDICATIONS:

· Glipizide 15mg twice a day.

· Metformin 850mg three times a day.

· Subcutaneous Humulin N 10 units every night.

· Enalapril 5mg every morning

· Simvastatin 15mg every night.

PHYSICALEXAMINATION

General appearance – Looks comfortable.

BMI – 33.8 (Height 1.72m and weight 100kg)

Nails – No pallor and clubbing seen.

Tongue – Moist and pink.

a) CVS examination

Pulse – 72 beats per minute. Regular in rhythm.

Blood Pressure – 136/90mmHg. Home BP is also around 140/90mmHg

Heart – Apex beat was palpable at the 5th intercostal space on the left mid clavicular line. There

were no thrills or parasternal heave felt. S1 and S2 heart sounds were heard. No murmurs were

detected. Jugular venous pressure was not raised. There was no pedal oedema.

b) Lungs examination

Lungs – Chest expansion was equal bilaterally. Bilateral vesicular breath sounds were heard

symmetrically. No crepitations or wheezes were heard.

c) Abdomen examination

Abdomen – Abdomen soft and non-tender. No lipohypertrophy seen. There is no organomegaly.

Kidneys are non-ballotable. There are no renal bruits.


Laboratory Tests

Aug 06 Sep 06 Nov 06

HbA1C% 8.8% -- 7.4%

FBS (mmol/L) -- 6.2 --

HBGM(mmol/L) -- 4.7 to 5.6 --

BP 130/80mmHg 146/90mmHg 142/90mmHg

LDL -- -- --

Medications

Glipizide 15mg BD

Metformin 850mg BDLovastatin 20mg ONAdd Humulin N 10 units

ON

TCU 4 weeks

Same Meds

TCU 8 weeks

Increase Metformin 850mg TDS

Add Enalapril 5mg OM

Others remain sameTCU 8 weeks with K+, Na+ andCreatinine

Jan 07 Apr07

HbA1C% 7.6% 7.9%

FBS (mmol/L) -- 7.5

HBGM(mmol/L) 5.6 to 7.6 5.5 to 5.7

BP 136/ 94mmHg 140/ 90mmHg

LDL 3.00mmol/L 2.80mmol/L

Medications

Wants to try diet modification instead of increasing

insulin.

Change Lovastatin to Simvastatin 15mg ON.

Others remain same.

TCU 12 weeks with HbA1C%, FBS, Lipids, ALT, AST.

Today consult.

DIAGNOSES

· Diabetes mellitus on insulin therapy

· Diabetic nephropathy

· Hyperlipidemia

· Hypertension

· Osteoarthritis knee


MANAGEMENT

In general, diabetes management of Mr Kwok should be focused on 3 main areas, glycemic

control, blood pressure regulation and cholesterol management.

MrKwok’s Glycemic Profile.Mr Kwok’s glycosylated haemoglobin (HbA1C%) deteriorated

from a 7.6% to a 7.9%. HbA1C% is a 3-monthly indicator of the glycemic control. An

acceptable HbA1C% of 7% might indicate a consistent level of blood glucose around 8.4mmol/L

, or may depict a range of too “high” and too “low” fasting blood glucose averaging to 7%. An

HbA1C% of 7.9% actually indicates an average blood glucose level of about 10mmol/L (Nathan,

Turgeon and Regan, 2007). However, in Mr Kwok’s case, his fasting home blood glucose is

5.5mmol/L to 5.7mmol/L. The pattern of a high HbA1C% in contrast to optimal home fasting

blood glucose readings indicates that Mr Kwok has many episodes of hyperglycemia in the midst

of his good fasting glucose readings. This led me to probe Mr Kwok on the change in his dietary

and exercise habits. He admitted to drinking Pokka Tea, Yakult and 100 Plus soft drinks about 3

times a week which are sugary drinks. These contributed to the increased HbA1C% from 7.6%

to 7.9%. His weight has also increased from 97kg to 100kg in a 3-month period. According to

Hirsch et al, (2005), the relative contribution of fasting glucose to overall glycemic control is

70% in patients with a HbA1C% more than 10.2%; this contribution of fasting glucose decreases

as HbA1C% decreases. Thus in Mr Kwok’s case, the focus will be on postprandial glucose

spikes.

I advised Mr Kwok to stop all his sugary drinks. Coke Light and Pepsi Light (soft drinks with

aspartame) are suggested to substitute his 100 Plus and Pokka Tea during hot weather. In

addition, asking him to add more fiber to his daily meals and drink more water to relieve his

constipation, in the hope that he can stop his reliance on Yakult. My intention is to lower Mr

Kwok’s postprandial spikes through diet control.

InsulinManagement forMr Kwok. Theoretically, the ideal insulin therapy regimen should

mimic normal physiologic insulin release. The risks of insulin therapy include weight gain,

hypoglycemia and, in very rare cases, allergic and cutaneous reactions (DeWitt and Hirsch,

2003). According to Mayfield and White (2004), the starting insulin dose for insulin therapy is

calculated as 0.2 units per kg per day. Another safe calculation is units of insulin per day equals


fasting plasma glucose level in mmol per L. Supplemental (or correctional) insulin is added or

subtracted to bring the pre-meal or bedtime glucose levels into the desired range. Insulin

sensitive patients require 1 unit of insulin to change the blood glucose level by 2.8mmol/L;

insulin-resistant patients experience a smaller change (Mayfield and White, 2004). Another

recommendation for dose titration in once-daily or twice daily insulin regimen is shown in Table

1 (Hirsch et al, 2005).

FBS Most Values

(during last 3 to 7 days)

Dosage Change

< 4.4mmol/L4.4 to 6.0mmol/L6.1 to 7.7mmol/L

7.8 to 9.9mmol/LMore than or equal to 10mmol/L

-2 unitsNo Change+2 units

+4 units+6 units

Table 1: Dosage Titration for Once-Daily or Twice-Daily Insulin Regimens

In Mr Kwok’s case, if we want to correct his night insulin regimen, his fasting blood glucose

during the consult of 7.5mmol/L has a difference of 2.5mmol/L when corrected to 5.0mmol/L. In

this scenario, an increase of 1 to 2 units of insulin to the night regimen might be appropriate. The

decision to increase night basal insulin should be carefully balanced between reaching the

optimal target, risks of hypoglycemic episodes and patient’s acceptance. For Mr Kwok, a small

incremental dose of basal insulin will not directly address the postprandial hyperglycemia,

although it might have a slight improvement in the overall HbA1C%.

I also advised Mr Kwok to provide a home blood glucose profile in the next visit for refining

insulin therapy. Prior to night insulin, glucose readings at about 10pm and 2 hours post lunch

readings will be useful in deciding the need to add morning insulin as the next step in

management. Thus during this consult visit, it had been emphasized to Mr Kwok that he had to

watch his diet, stop all his sugary drinks and perform 2 hours post lunch and pre-night time

injection glucose readings.


Should we maintain the combination of OHGA with insulin or slowly reduce OHGA to keep Mr

Kwok’s on insulin alone? There had been studies that Metformin with insulin causes less weight

gain, lower insulin requirement and fewer hypoglycemic episodes than insulin alone or insulin

with Sulfonylureas (DeWitt and Hirsch, 2003). Metformin and insulin seem to be the best

combination for majority of Type 2 diabetes patients unless contraindicated. Combining

Sulfonylureas with insulin has also shown to reduce insulin doses by 25% to 50% with less

weight gain. However, as insulin production declines and HbA1C levels approach 10%, the

combination of insulin and Sulfonylureas eventually becomes ineffective. Since Mr Kwok’s

HbA1C% is below 8% for the time being, it is appropriate to continue using Sulfonylurea in the

management. However, I will monitor Mr Kwok’s renal function closely and start to decrease the

dosage of Metformin and increasing insulin dosage in the next few visits if indicated.

Cholesterol Management.Mr Kwok’s low-density lipoprotein level (LDL) has dropped from

3.0mmol/L to 2.80mmol/L with a change of Lovastatin 20mg to Simvastatin 15mg in the last

visit. He is tolerant to the statins as Mr Kwok did not experience any side effects like muscle

pain, tenderness or weakness and his liver enzymes remain in the normal range (ALT: 18U/L,

AST: 17UL). However, the LDL reading has not reached the intended target of less than

2.60mmol/L for diabetic patients. Mr Kwok’s initial LDL is unknown to the polyclinic as he was

already started on Lovastatin 10mg prior to joining Hougang polyclinic. The initial LDL level

prior to treatment will be a good guide for the estimation of statins dosage. In this case, a step-

wise increase of Simvastatin 15mg to 20mg with reinforcement in diet control and exercise will

be appropriate. The expected reduction of LDL on Simvastatin 20mg versus Lovastatin 20mg is

about 32% to 29% (Law, Wald and Rudnicka, 2003). Liver enzymes have to be rechecked in 2

months especially in elderly and those with impaired renal function when dosages increase.

Fasting lipids can also be monitored about 3 months apart to evaluate the effectiveness of

increased statins dosage.

Blood pressure management. Blood pressure control for all diabetes should be less than

130/80mmHg. For a diabetes patient with overt nephropathy, the blood pressure target is

120/75mmHg according to Ministry of Health, Diabetes Mellitus Clinical Practice Guidelines

(2006). Mr Kwok was newly diagnosed to have hypertension with 3 episodes of elevated blood

pressure readings at the last visit. Based on today’s consult blood pressure of 140/90mmHg, his


blood pressure control is considered sub-optimal. Mr Kwok has early diabetic nephropathy with

albumin : creatinine ratio (ACR) of 30 to 300mg/g. Mr Kwok was already on Enalapril 5mg

every morning which is appropriate, as recommended by the guidelines that ACE inhibitors

introduction can retard progression of renal disease. In retrospective, as Mr Kwok is only on

Enalapril 5mg every morning, it will be appropriate to optimize his management by increasing

the Enalapril 5mg to twice a day for better blood pressure control.

Early diabetic nephropathy management. In Mr Kwok’s case, good glycemic control is important

as it can delay renal disease progression. Yearly, monitoring of ACR is essential. If the ACR

goes beyond 300mg/g, 24hours urine total protein (UTP) and creatinine clearance test (CCT)

ought to be done and monitored 6-monthly to yearly depending on the severity. However, there

are also limitations in obtaining a representative urine collection for 24hours protein and

creatinine evaluation in the polyclinic setting. Thus, serum creatinine levels can be used to

calculate the glomerular filtration rate (GFR) using Cockcroft-Gault equation or MDRD formula.

In NHG Polyclinics, the Chronic Disease Management Registry is an electronic database that

captured all the chronic patients’ clinical indicators and it is able to generate the estimated GFR

(eGFR). Mr Kwok’s eGFR for January 2007 with a creatinine level of 103mmol/L was

66ml/min/1.73m2. The GFR calculated from serum creatinine level however needs to be used

with caution as there are certain factors that rise creatinine levels e.g. fever, exercise, increasing

age, muscle mass loss etc. Limitations aside, GFR is a good estimate of renal function in the

management of a diabetes patient with microalbuminuria. Besides, staging the progression of the

chronic kidney disease, the GFR also serves as a guide to diabetes management e.g. needing to

stop long-acting sulphonylureas and metformin when it reaches Stage 3 <60ml/min/1.73 m2.

Referral to the renal specialist is warranted if Mr Kwok has any of the following: a) creatinine

goes above 200umol/L, b) 24hrs UTP >1g/day, c) CCT <30ml/min, d) proteinuria associated

with haematuria, e) poorly controlled blood pressure, f) presence of a renal bruit, g) unexpected

or rapid decline in renal function e.g. acute on chronic renal failure secondary to conditions

leading to hypovolaemic status like GE and h) difficulties in hyperkalaemia. Management of

early diabetic nephropathy includes minimizing further damage to kidneys e.g. treat urinary

infection and avoid use of non-steroidal anti-inflammatory drugs (NSAIDs).


Mr Kwok was discharged from the consult with the following medications:

1) Glipizide 15mg twice a day.

2) Metformin 850mg three times a day.

3) Subcutaneous Humulin N 10 units every night.

4) Enalapril 5mg every morning

5) Simvastatin 20mg every night. (Increased0

Mr Kwok was given 8 weeks follow-up appointment. During the next follow up, the following

tests will be done 2-hour post-prandial glucose and liver enzymes (ALT and AST).

EVALUATION

During the next follow up appointment, evaluating the following as part of the management is

appropriate: (a) liver enzymes in relation to increased statins (b) health behavior change in

substituting or stopping all sugary dinks and (c) home blood glucose monitoring profile of 2-hour

post lunch and pre-night injection readings. Evaluating the clinical blood pressure and home

blood pressure readings which had not been emphasized during the last consult should be

considered seriously in the next consult. The 2-hour post prandial glucose and home blood

glucose profile will give a guide to the need for converting once-daily insulin injection to twice-

daily regimen. The decision to change the insulin regimen to twice daily will require the

practitioner to assess the timing of the meals and ensure strict consistency of the timing of

injections with meals.

APN RFLECTION AND LEARNINGPOINTS

This is one of the typical Diabetes Mellitus patients an APN will manage in the polyclinic

setting. From this case study, I have learnt insulin management in elderly and the clinical

decisions required according to the change in glycemic indicators and overall physiological

changes (e.g. renal function, hepatic function, etc.). I have also learnt the management of

Diabetes Mellitus which encompasses managing hypertension, hyperlipidemia and screening of

diabetes complications.


REFERENCESDeWitt, D.E. and Dugdale, D.C. (2003). Using new insulin strategies in the outpatient treatmentof diabetes – clinical applications. Journal of American Medical Association, 289(17), p. 2265-

2269.

Hirsch, I.B. et al (2005). A real-world approach to insulin therapy in primary care practice.

Clinical Diabetes, 23(2), p.78-86.

Law, M.R., Walk, N.J. and Rudnicka, A.R. (2003). Quantifying effect of statins on low density

lipoprotein cholesterol, ischaemic heart disease and stroke: systematic review and meta-analysis.British Medical Journal, 326, p 1423-1430.

Mayfield, J.A. and White, R.D. (2004). Insulin therapy for type 2 diabetes: resuce, augmentation,and replacement of beta-cell function. American Academy of Family Physician, 70(3), p.489-500

Ministry of Health (2006). Diabetes Mellitus Clinical Practice Guidelines.

Nathan, D.M., Turgeon, H. and Regan, S. (2007). Relationship between glycated haemoglobinlevels and mean glucose levels over time. Diabetologia, September (13), retrieved from

http://www.springerlink.com/content/33x337022x781218/fulltext.pdf on 13 September 2007.

case study 10 -- elderly on insulin therapy

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